I remember when I did an install in my Mom's (formerly mine ...kinda) 95 Avalon. Luckily my dad had purchased the shop and electrical wiring books for the car.

It also had the 6 speaker system in it, however to my knowlidge, the 4 speaker system also had the seperate amp and no wiring harness was available (at least for 95/96). My Aunt's 98 has the 4 speaker system with single disc CD and also has the extenal 170 watt amp.

 

95 avalon

Thank you, the info about bypassing the factory amp was very helpfull. I would like to mention one problem I ran into that may be helpfull to others attempting this venture. I could not get my power antenna to work even after trying the wires you described. After looking at the wiring diagram in the haynes manuel I realized the antenna requires two power supplies, one from the head unit and one from the amp. By trial and error I found the two wires and connected them to my antenna wire. The wire at the head unit was black with a red strip. The one at the amp was red. I imagine that the wiring may have changed a little from year to year.

 

This is great! Would've been better a year ago when I installed mine.

I went ahead and made myself a wiring assembly to connect between the existing harness, the speakers, and my new unit. This way if I sell it I can reinstall the old unit. As it turns out I've since given up on that idea and tossed the old unit.

Where'd you mount the accessory plug?

 

Old thread, i know. So for this u just need a wiring harness if u have 6-7 speakers? Also approx how long this take you?

 

Great instructions and write-up, but there is a plug in wiring harness adapter available for 95-99 Avalon systems with the factory amp that makes the whole re-wiring thing moot - it is made by Metra, it is available through Crutchfield
http://www.crutchfield.com/App/Product/Item/Main.aspx?g=103000&i=120708112&c=3&tp=736
and also pops up on E-bay from time to time (be careful, it is NOT the regular two-plug Metra Toyota Avalon/Camry set that you see for $3-$4), costs about $12.99, makes installation a snap. The replacement radio must have two RCA pre-amp outputs to use the adapter/factory amp, most better units sold nowadays do. I will be using this adaptor to install a JVC KD AVX-1 Receiver/CD/MP3/WMA/DVD player with built in screen.

 

Great instructions and write-up, but there is a plug in wiring harness adapter available for 95-99 Avalon systems with the factory amp that makes the whole re-wiring thing moot - it is made by Metra, it is available through Crutchfield
Metra 70-8112 Receiver Wiring Harness Connect a new car stereo in select 1992-2000 Lexus and Toyota vehicles at Crutchfield
and also pops up on E-bay from time to time (be careful, it is NOT the regular two-plug Metra Toyota Avalon/Camry set that you see for $3-$4), costs about $12.99, makes installation a snap. The replacement radio must have two RCA pre-amp outputs to use the adapter/factory amp, most better units sold nowadays do. I will be using this adaptor to install a JVC KD AVX-1 Receiver/CD/MP3/WMA/DVD player with built in screen.

 

I am trying to replace the original stereo with aftermarket one in my 1993 Previa. The wire schema on the Amp output is the same for all Toyotas after 1987. My wire harness for the Amp input looks a like the one you have explained. Correct me if I am wrong but does this mean that you totally bypass the factory Amp. Is there any other way to install aftermarket stereo and keep factory amp? If so could anyone post how to pair wires of Amp input harness to aftermarket stereo?

 

The adapter bypasses the subwoofer function of the factory amp. AFAIK the speaker outputs are still being routed through there, but I never delved that much in the wiring schematics.

 

Now you have to get to the factory amp, which is behind the glove box.

Start by removing the right kick panel. It has a plastic bolt, then you just pull it off.

Your next step will be to remove the L shaped trim panel, with also has a cover attached to it, behind it. This cover came off easily as I removed the L shaped trim panel. The L shaped trim panel has three bolts. Two are easy to see. The third you have to open the glove box and remove a cover to see:

http://drri.home.comcast.net/avalon/L_shaped_trim_bolt.jpg

After you removed the bolts, you will pull off the L shaped trim piece. I had to play with opening and closing the glove box door while getting it off. This next pic will help so you know where the tabs are that holds it in.

http://drri.home.comcast.net/avalon/L_shaped_trim_clips.jpg

The glove box door comes off easily with three bolts.

Four screws hold the actual glove box, and there are connectors that have to be removed, including one that I think runs to the air bag (oh year, before you batter is disconnected). You will have to work a little to get the glove box proper out.

When you finally get it all removed, this is what you will see:

http://drri.home.comcast.net/avalon/amp.jpg

That is your factory amp on the right, with two connectors in it. It is attached with two bolts on the rear side of it.

Here is a closer look at the plugs:

http://drri.home.comcast.net/avalon/amp_plugs.jpg

What I did to work with these was to cut back the insulation about an inch. It’s tight, but there was enough room to reach through the glove box, strip wires, and attach new wires. If you do not have a wire stripper already, buy the smallest one you can. Mine is quite large and was cumbersome to work with.

You will basically end up running 10 wires from here to new head unit (8 speaker wires, constant power, and accessory power).

You can consider the blue (white in some Avalons) one the output—out to the speakers, and the green (grey in some Avalons) the input-inputs from the head unit. From the input one you will only draw your Accessory Power. Not sure why, but Crutchfield recommended drawing power from the one I am designating output.

Here is the wiring schema for each plug courtesy of Crutchfield:


White or blue plug at amplifier (output)

FUNCTION / WIRE COLOR

Right Front SPKR + / LIGHT GREEN – this and the next 3 go to new HU

Left Front SPKR + / PINK

Right Rear SPKR + / RED

Left Rear SPKR + / BLACK

Woofer + (7th SPKR) / GREEN/BLACK – missing on mine

Constant 12 Volt Input / WHITE/BLUE – where I drew power

Right Front SPKR - / BLUE – this and next 3 go to new HU

Left Front SPKR - / VIOLET

Right Rear SPKR - / WHITE/BLUE

Left Rear SPKR - / YELLOW

Chassis Ground / BROWN – the ground I used

Chassis Ground / BROWN

Woofer - (7th SPKR) / GREEN/RED – missing on mine

Constant 12 Volt Input / WHITE/BLUE




Gray or light green plug at amplifier (input)

FUNCTION / WIRE COLOR

Remote Turn On / RED – you could do your antenna power here, or where I mentioned earlier

Accessory 12 Volt Input / GRAY – where you get your accessory power

Constant 12 Volt to Radio / WHITE

Beep Input from Radio / BLACK

Left Front SPKR + Input / GREEN

Right Front + Input / RED

Illumination Input / GREEN

Illumination Output to Radio / GREEN

Accessory 12 Volt to Radio / BLACK

Chassis Ground to Radio / BLACK

Signal Ground Input from Radio / BROWN

Mute Input from Radio / BLUE

Left Rear SPKR + Input / WHITE

Right Rear SPKR + Input / YELLOW

Thanks for the great writeup SickWilly. Not sure if you're still around or if anyone else can help. I followed these instructions and found no amp under the glove box of my 1999 XL, with 4 speaker system. I suppose that means I don't have an amp (which is counter to what some people have said that ALL Avalons before 2000 came with an amp.)

My question is what wiring harness do I need, or does someone have the wiring harnass schematic for the stereo without the amp. I bought an inexpensive Pioneer DEH-11E to replace the factory head unit. I'm glad I don't have an amp because the Pioneer doesn't have preamp out. I plan on either making an adapter plug or splicing into the existing cable but need to know what wires go where.

 

This was written quite a while ago, if you are looking for a simpler install, I'd recommend just getting the wiring harness adapter that crutchfield recommends. There is no longer a need for rewiring the amplifier, even if you have one. This is most likely the wiring harness you need(you should probably contact crutchfield if you want to make sure): http://www.crutchfield.com/p_120701761/Receiver-Wire-Harness.html?tp=2977

If you want to make your own cable, here is a factory diagram of the sound system wiring: http://www.tundrasolutions.com/forums/avalon/64306-1996-avalon-radio-diagram-help/

 

Thanks for the links to the diagrams. I bought those harnesses, from Ebay...as well as the DIN pocket. Whole mess cost $25 bucks including shipping. I just wasn't sure how to wire them...not sure if they will come with instructions on what each color wire is, or if I have to know the original wires...which is why I was looking for a diagram.

I am a bit concerned though, because the nhparrot posted a pdf that shows an amp behind the radio. I was hoping I wouldn't have any kind of amp to deal with (since I don't have a radio with preamp outs.) If I find one there I'll have to wire around it.

http://www.tundrasolutions.com/forums/attachments/avalon/13082d1149241626-1996-avalon-radio-diagram-help-loca.pdf

 

That diagram is paired with the diagram showing the subwoofer, which is NOT the 4 speaker system. Also, the pages following that one in the manual state different troubleshooting steps for with or without an amplifier, so no, the 4 speaker system does not have an amplifier.

 

Thanks...and you are up early....like me.

The main impetus for changing out the stereo was getting an auxiliary input. Previously we had gone through a couple cheap tape adapters and FM transmitters and a good one...or antenna bypass, was as expensive as buying the Pioneer CD receiver ($60.) I will be happy to not have to deal with inputting the radio code every time we remove power too.

P.S. Anyone know what the power output of the stock radio was? The Pioneer is 14 RMS watts x 4 channels.

P.S.S. Anyone added a rear sub to a system that didn't come with one? The Pioneer has rear preamps out. Down the road might add an amp and rear sub, but wonder what is the best way to get the wire back there (I see there is already a speaker housing under the rear shelf.)

 

I have been unable to find any sort of specifications on the original speaker power. But I'm pretty sure that the pioneer unit will work out just fine without any amplifiers or anything.

Also, I'd assume that the rear outputs are intended for a subwoofer output instead of a rear output. You would need to run a power wire from the battery to the trunk, and the signal wires from the rear pre-outs to the trunk(also you will need to run a wire to tell the amp when to turn on(remote wire)), you'd run these cables on opposite sides of the car, under the carpet, under the doors. You can get under the sides of the carpets without any tools by just lifting up the plastic things on the bottom of the door frame.

Also, if you are installing a subwoofer in the trunk, you would be better to go with a box. This is because 8 inch free air subwoofers are hard to come by, and probably won't give you sound comparable to a subwoofer in a box.

 

After looking at the cost and hassle of a rear sub setup, I may just go with an integrated amp/sub like this one.

http://www.amazon.com/Boss-BASS600-Low-Profile-Amplified-Subwoofer/dp/B000OSZA44/ref=pd_sim_e_1

It gets decent reviews and would be a nice supplement to the 4 inch door speakers.

I'd probably either go under the seat or up under the dash. The dash would be more convenient (shorter wires to run) but I'm concerned that might cause rattles, or vibrations.

 

Just got done installing a Pioneer DEH-11E into our 1999 Avalon LX. Ours has 4 speakers and no amp and the TWH-950 10pin and 4 pin harnesses worked perfectly. Because we had no amp we only had to monkey with center dash console. The Pioneer, despite being a "value" model, definitely has more power than the stock radio...have to be careful not to blow the stock speakers. Metra 88-00-8000 pocket used to fill unused DIN space.

Had a couple issues...pretty minor.

First it was really hard to pull off the dash cover, and 3 out of 7 of the metal clips popped off when we did. Could hear them rattle down inside car. Was afraid we were snapping off something plastic. Interestingly, we popped all the rest off before reinstalling the cover back on (because we plan on adding subwoofer and wanted didn't want to fight with the cover when we do) and it still snapped hard into place???? Hope we can pick up the clips from the dealer for not outrageous price.

The Pioneer head unit had a sliding metal sleeve over it. Must be used for certain installs. At first we didn't realize and had a heck of a time installing the brackets because with the sleeve the stereo was too wide.

The trim cover, around the stereo interfered with the Toyota dash cover. We had to leave it off. This will make reinstalling the pop off faceplate trickier because the trim plate helped align it. I'm considering just snipping off the faceplate removal button. It isn't likely someone is going to steal an $80 dollar radio (actually got it for $60, on clearance, because the 12E model is now out.)

The 99's don't have a power antenna so I wasn't sure whether to hook up the blue wire. In the end, we did...but now realize we'll have to splice into it for the amp switch.

For the amp we plan on just splicing into the cigarette lighter power. Should have plenty of power from that.

Did purchase the combo amp/8" (Boss BASS600) sub for $100 and will install under the seat when the install kit we ordered arrives.

http://www.bossaudio.com/main/649

 

How did the Boss Combo amp/8" work out?

 

It's been working great. It just fits under the driver seat...there is a bit less toe room under the seat for the passenger behind the driver....maybe 2-3 inches. Decided not to mess with cigarette lighter splice. Bought the Boss install kit and it came with a long power line run (10 feet or so.) Ran the wires along the tunnel, under the dash and through the firewall above the emergency brake to the battery. Hooked ground to seat rail. Left the gain adjustment knob and cable down under the seat as it isn't something you need to adjust once it's set.

 

Outstanding post, thank you much Sickwilly I was puzzled by the extra connector behind the stereo at first. I was working on installing an aftermarket cd deck to replace the original 3 disc changer and also was puzzled by the seeming inconsistency between the diagrams and the wires I was cutting. I now see that all I did wire correctly was the battery, accessory, and ground. I would never have guessed there was an amp behind the glove box, so I guess that is where I will have to go to get sound to the speakers. It would have been easier to buy the adapter, but I always tend to do my own splicing, etc. Guess this will take just a bit longer than I'd hoped, but thank you for the pics.

 

Ok. So im a bit confused about my 98 Avalon XL. It has 4 components and the sub in the rear. Does this mean it has the factory amp? Also, it has the single DIN factory, so will i be needing a dash kit for an aftermarket single DIN unit?

 

Excellent write-up, SickWilly! Looks like you got your technical advice from some real experts! Too bad we don't get to hear your system.

One little note (although it's a little late now!) and I don't mean to slam Crutchfield because I bought tons of stuff from them in the past. They used to be super cheap and no local stores would beat their prices. In fact, if you walked into a stereo place carrying a Crutchfield catalog, they would often get rude with me! They couldn't come close to those prices. Not anymore! Over the years, Crutchfield has become often more expensive than local stores! Really. I still use them as an excellent source for info, but when it comes to purchasing equipment, I discovered SonicElectronix is the newest place to get the best prices and customer service. E-mail them a question and someone will call you the minute they open! I have had so many excellent experiences with SonicElectronix that I haven't purchased from anyone else in the last 2 years. Just wanted to put a bug in your ear for checking prices on future equipment. I purchased 90% of my last car's stereo gear from them.

That's cool that you posted that wiring diagram. I save wiring diagrams for any stereo or vehicle I ever work on, so they come in handy. But I haven't done an Avalon yet.

I'm guessing your system rocks hard! Very nice install job. Seriously. I've been installing car audio and security for over 30 years (but never professionally, only for a 2nd added income for friends, family and myself) and can always spot a well-planned and thought out install that was painstakingly done. Yours looks awesome! You owe yourself a pat on the back! If you ever have a question concerning car audio or alarms, feel free to ask. I may not be an "official expert" but I do offer free advice! I have hundreds of notes and schematics on everything from relays to diodes to sensors to adjusting gains and hooking things up. Just an offer. It's up to you. And if you really find yourself starting to get heavily into the car audio for your Avalon, you need to join the forum "the12volt.com" which is where I've learn tons of tricks and tips!

This is the last system I did in my last car, a 98 Dodge Stratus (haven't done a thing to my Camry besides install an Alpine deck. Factory speakers, no amp, nothing). Unfortunately, I was forced to sell the car and all the new equipment!

http://s254.photobucket.com/albums/hh100/Hairball98498/98 Stratus stereo/

Again, very nice write-up! I couldn't have done that good myself!

 

I have a 95 Avalon w/ the 6spkr system in it (no subwoofer). We had an Alpine head unit installed back in 95 and Circuit City bypassed the factory Amp. Now the unit is starting to act up and my parents want the factory tape deck reinstalled. Im planning to tackle this myself, and I know for a fact that the factory amp has been bypassed. I have a double din OEM Scion deck that I would like to install in it. I want to know the following,

1) Are the harnesses the same?
2) Will I need to connect the wires to the factory amp?
3) If anyone has done this, can they post up some pics?

Thanks in advance!

 

95 Avalon Stereo Install

I just installed an aftermarket HU in my 95 Avalon XLS, factory 7-speaker w/amp. I ran into some issues I have not seen addressed in any of these write-ups, and I wanted to share my solutions and observations.

First, thank you thank you to slickwilly, swiftjustice, and everyone else who has contributed to these threads. The info was invaluable!

So here's what happened:

I have a JVC KD-HDR50. I had previously installed it in a 96 Hyundai Elantra Wagon, using a Metra harness adapter, easy install, easy removal when I traded up from the wagon to my Avalon. No problem.

I read everything I could find online about stereo swaps in these cars. Very, very helpful, and I was then braced for shinanigans.

My JVC HU has 4 RCA outputs, so I figured I could use them to get an un-powered signal to the factory amp. I'm too cheap to pay 15.00 for a harness when I have big piles of RCA cable in my closets, so I decided to splice everything by hand.

Here is a link to Crutchfield's information on this car:

http://crutchfield.custhelp.com/app/answers/detail/a_id/7401/kw/1995 avalon

The three connectors on that page aren't clearly labeled. The white one they show at the top is the connector at the back of the factory head unit, most of it's wires lead to the amp. The two lower connectors are plugged into the amp, behind the glove box. The one on the left is the output from the amp to the speakers. The one on the right is the input from the stereo HU to the amp. In my car they were blue and green, respectively, but I understand they can be different colors.

So, I connected my JVC's power and such by cutting the wires at the factory stereo connector in the center of the dash and twisting in.

One small note there: you will notice that the factory connector has 2 pins for lighting the HU. Pin 2, "Illumination", and Pin 9, "Dimmer". The First time through I connected Pin 2 to the orange "Illumination" wire in my JVC unit. When I turned it on, all of the display was lit up like christmas, with every symbol lit. Too much power. Second time through, I connected to Pin 9. Now the display behaves the way it should, and responds to the dashboard dimmer circuit when the car's running lights or headlights are on.

I had read about making sure to connect to the amp's remote-on lead, which is Pin 1 at the connector. My new HU has a blue wire just for that. I understand thay they pretty much all do. Sweet.

Then comes the first snag. What to do with the RCA shielding? I have some experience with installing shielded wiring for VOR and radar receivers, but I wasn't totally sure that this was the same thing, so for the time being, I simply connected the center signal pins of my RCAs to the 4 Positive leads going to the amp, Pins 6, 7, 14, and 15. I twisted up the shields and taped them back to the insulation to keep them out of the way. Some of you already know what happened next.

When I got everything hooked up and reconnected the battery, the stereo powered on and I had sound - at the front speakers only. As I mentioned, the display was on fire, so I knew I had guessed wrong about the illumination power. I turned on the car's headlights to see if that would affect the display, and I got a loud, clear, evil hum from the front speakers. Ya. Shielding has to go somewhere. I had a very strong suspicion that that's what Pin 12, "Signal Ground", was for. But I wasn't totally certain whether the RCA shielding should go there, or should ground to chassy. So I read more. Here are some awesome articles about audio grounding:

http://www.rane.com/note151.html
http://www.rane.com/note110.html

and this thread was helpfull too:

http://www.diyaudio.com/forums/solid-state/155438-signal-chassis-ground-wiring-rca-xlr.html

If you look around on the net, there is a whopping metric ton of info on the subject. Back to our Avalon.

Turns out Toyota was just way ahead of the curve back in 95. They used an isolated signal ground in their factory radio, which gives you very clear sound, free from interference and EF noise. But in order for it to work, it has to be connected to the chassy ground *internally* at either end of the chain - in this case, at the stereo HU and at the amp. Fortunatly, this is how all RCA connectors are wired in aftermarket stereos. So I determined that by simply connecting the shielding of all 4 RCA leads to Pin 12, "Signal Ground", I would eliminate all of the noise and interference. Cool.

Before doing that, I decided to make sure everything else was working properly, so I ran the JVC through it's paces. I used all of the input options, radio, cd, ipod, played with the fade and the eq, and quickly found snag #2.

The front speakers sounded great. The rear door speakers sounded muddy and quiet. I couldn't hear the subwoofer at all. Nuts. Being somewhat familiar with the internals of my JVC unit, I got into the menus and played with the settings. I found that by switching it's internal crossover to pass as broad a range of frequencies as possible to the sub, and then turning the subwoofer gain all the way up, and then fading everything way toward the back, I could get sound out of the sub. But the rear door speakers still didn't sound like they were doing much, and the overall sound in the car was very, very quiet in the lower mid-range frequencies. Curiouser and curiouser. But I had kind of thought something like this might happen.

The RCA outputs on the HU are not labeled left and right, front and rear. They're labeled left and right, Front and Subwoofer. JVC had assumed that most people would use the powered speaker outputs from the HU's pin connector to drive their car's front and rear door and deck speakers, and optionally, maybe decide to connect a subwoofer, and an accompanying amp, to the RCA subwoofer output. Therefore, they had the sub-out filtered to the appropriate frequencies. The filter is adjustable to three levels, as I mentioned. But it just doesn't go up as high as the rear speaker outputs.

So my dilemma became this: If I used the un-powered RCA outs to the factory amp to the speakers, I had poor sound, but I had the subwoofer. If I used the powered outputs, I'd have to bypass the amp, straight to the speakers, I'd have full range of frequencies, but no subwoofer, unless I bought a subwoofer amp. (This is what sickwilly did in his car.)

Some of you may be asking, "But why not just go into the JVC's menu, and use the Internal Amp Switch to make the speaker outputs un-powered? Then you could connect to the factory amp, which would give you the full range of signal, and let the amp drive all 7 speakers. Just like the factory stereo did."

I thought about that. But then I remembered that the speaker outs from the JVC are 2-wire. One positive and one negative for each speaker. The inputs for the amplifier are only one positive for each speaker, and a common Signal Ground to provide reference and grounding for the whole thing. I called a few installers, and no one knew of a way to connect those two things together. Nuts. Again.

I didn't want to buy a sub amp. The whole point of this project was to spend as little cash as possible.
Then, while I was on the phone with BestBuy's stereo installation team manager, who kept saying helpful things like, "Wow, that's messed up. I dunno, man." it hit me. I already had a subwoofer amp. Toyota had put one in the car, right behind the glovebox. Duh. Duh. Duh.

So this was my solution: I used the powered outputs from the JVC's connector, bypassing the amp, straight to the speakers. Wiring them into the amplifier output wires under the glovebox was joyfull, only the opposite of that. By the way: you don't have to do that work *through* the glovebox opening. Once you unplug the connectors from the amp, you should have enough harness to gently pull them down, so that they're hanging out *under* the dash. This gave me a bit more room to work. The resulting bundle of 8 wires going from the area of the amp to the area of the stereo tucks very nicely into the trim rail that forms the bottom of the glove box opening.

Then, I wired the RCA Subwoofer outputs from the JVC to the factory amplifier input, at the factory stereo's connector, like this:
Sub-Out Left : center wire to Pin 14
Sub-Out Right: center wire to Pin 15
The shielding for the RCA cables, I twisted together, and ran *both* of them to Pin 12, Signal Ground.

Another note on grounding: Because of the way Toyota wired this equipment (ahead of their time, remember?) it is very highly advisable to be sure that, if you are going to used the factory amplifier at all, Pin 11 on the stereo connector should be tied to a chassy ground somewhere. In the original stereo, this went to the unit's frame internally, I think. In my application, I teed the wire from Pin 11 to the Chassy Ground wire coming out of my JVC, and bolted them both down to the dashboard bar. If you look forward through the hole where your stereo used to be, you'll see a steel tube, about 1-1/2" diameter, running from left to right behind the dash. A few inches toward the passenger side from center of the car, there is a grounding point with a very convenient 10mm nut. I'll try to get a picture of it when I pull the stereo to install the dash pocket later.

So. After all that, everything connected, screwed back down, and the dash re-assembled, the stereo sounds great! I still have the subwoofer settings in the HU cranked all the way up - the front door speakers are a bit overpowering, and I have it faded back a little bit, maybe 3 or 4 out of 10. The little 8" sub hits pretty good, and all of the door speakers sound remarkable good for their age. (Anyone know who made them? I've heard that some of Toyota's speakers are JBL, but I don't know if that applies to these older Avalons.)

You might have noticed that I didn't say anything about connecting power for the powered antenna. That's because mine was broken when I bought the car. Motor works, mast is snapped off and corroded into a permenantly retracted position. I replaced the whole thing with a 7-dollar 31" one-peice Metra whip from Autozone. 10-min install, and I think I can get radio from Japan on the thing. Toyota used industry standard connectors for their antenna lead from the stereo to the trunk, so no adapter was needed to plug in the new antenna. Many, many blessings on them!

I think that's about it. This post got a lot longer than I intended, but I hope it's usefull. I'll edit in some pics when I get a chance, but I was on limited time when I did the job, so I didn't get any shots of the process, or my ugly, ugly wiring job.

Now I'm off to find out where the power steering fluid is leaking from. Yay!

Edit:

I just remembered (right after posting of course) that I wanted to say something about the Metra harness that is available. You know, the one with the 4 RCA leads, that plugs into the stereo connector in the center of the dash.

I haven't held one of these in my hand, so take this for what it is - conclusions logically deduced from research and observation.

I've read several people talk about using this harness to "bypass the factory amp", or say that it will "bypass the subwoofer portion of the factory amp." It seems to me that neither of those things are likely to be true. Here's my reasoning.

The Metra harness connects to an aftermarket head unit, and to the car's stereo harness, which is where the factory stereo plugs into the factory amplifier. Therefore, it is not bypassing the amp. It uses the RCA outputs to send an un-powered signal with a common signal reference (signal ground) to the amplifier. The amp powers the speakers. Which brings me to the second point.

The factory amp only receives 4 signals: front left and right, rear left and right. It then amplifies and splits the signals to 5 ouputs: front left and right, rear left and right, and subwoofer. (I'm pretty sure the 1" front door tweeters are jumped off of the front door speakers. Baseless assumption on my part.) So, if the Metra harness is sending the signal to the factory amp, the amp will power the subwoofer. If the subwoofer sounds very weak or quiet, I think it would be because the head unit's "rear speaker" rca output isn't pushing frequencies low enough and hard enough to really push the sub. If the head unit has 3 pairs of rca's, front, rear, and sub, this would be a very safe assumption.

Just throwing in an extra .02!

 

Has anyone with the factory amp in their Avalon tried using the harness swiftjustice mentioned for use with that setup? I'm confused because the Crutchfield page says "you will need to run the harness wires from your receiver location to your factory amp location" in the description. But it looks like the 4 RCAs go directly into your head unit, and the 5 other wires are spliced onto the wires from your head unit's harness. Unless they just mean the illumination wire, since it's missing from this harness, I can't think of what you'd be running directly to the amp.

Also, I found this harness, which looks to be the same, but clearly has the illumination pin/wire: http://mobile-emotions.com/twh-x14-00-0-3-toyota-avalon-1995.html Does this look like it would work (I can't tell if it has all the pins it would need from the pics)?

 

I have the harness from Crutchfield. You are right, the RCAs goes the pre-out on the Head Unit. The other wires go to Power, Ground, etc. The amp turn on wire from the headunit will need to go to the amp wire and antenna wire. I was wondering why fm wasn't working when I first installed it.

This kinda shows you how it works. I used wire loom to clean stuff up.

I also installed a homelink garage opener, in the storage tray.

 

I have the harness from Crutchfield. You are right, the RCAs goes the pre-out on the Head Unit. The other wires go to Power, Ground, etc. The amp turn on wire from the headunit will need to go to the amp wire and antenna wire. I was wondering why fm wasn't working when I first installed it.

This kinda shows you how it works. I used wire loom to clean stuff up.

Thanks for the pics. So nothing had to be wired from the head unit with new wire running all the way to the connections at the amp? You just plug the 4 RCA's into your pre-outs and splice the 5 wires on the wiring harness (12V, Accessory, Ground, Amp, and Antennae) to the corresponding wires out of your head unit, correct? It looks like that's what the first pic shows, but I just see an extra red wire hanging out and down in front of the climate control (can't see where the other end goes), and I think I see a black wire from the harness going back down into the dash on the left side.

I'm installing a 1-din deck and a 1-din ipod dock I make for a friend, so I'm trying to have everything ready to go in as quickly as possible so I don't need access to their car more than once. All the posts here have been very helpful. If anyone knows, I just had a couple more questions:

1) EDIT, SOLVED: I was able to check by just removing the corner kick-plate that has a thumb screw and saw the corrugated metal that must be the side of an amp (same as my Camry and as slickwilly pictured). I would definitely have to remove more panels to get at the wires, but I'll just work in the center console and go through the original wires to the amp. Is there a way to confirm the car (95 XL) has an amp without removing the kickplate or the stock radio? Slickwilly's pics show where it is, but I can't tell if you can see or feel it with the kickplate on. From what I remember when looking in the car, the plates covered everything. I'd hate to get everything purchased and built and discover that in fact some 95s DON'T have an amp.

2) Is it easy to access the cigarette lighter cables with just the stereo out, or do I have to remove the climate box below the stereo to splice to them? I want the ipod dock to charge, and I'd rather it do it 100% internally than loop wires out and back in. The lighter wires should already be routed through an appropriate fuse so I think these would be the ones to use.

Thanks!

 

I've just bought this Pioneer DEH-6300UB receiver from Crutchfield.

http://www.crutchfield.com/p_1306300UB/Pioneer-DEH-6300UB.html?tp=5684&nvpair=FFBrand|Pioneer

They come with free box and wiring harness. Hopefully this will work on my 1998 Avalon XLS, 7 speakers. I think it has a factory amp too. Will the amp work if I just connect the wire harness to the factory wires? I am thinking of running the amp kit (power, ground and RCA) wires to the trunk too. Just in case I want to add a separate sub & amp in the future.

Although, I am happy with the factory sounds, but the factory stereo is missing some buttons (to change the radio channels) and the factory HU doesn't have mp3 and ipod ready. The reason I want to replace the HU because I want the same sound (or better) with mp3/ipod ready compatibility.

Overall, I love this Avalon (I just sold my Lexus IS350 because it's too tiny for my two little boys).

 

I've just bought this Pioneer DEH-6300UB receiver from Crutchfield.

http://www.crutchfield.com/p_1306300UB/Pioneer-DEH-6300UB.html?tp=5684&nvpair=FFBrand|Pioneer

They come with free box and wiring harness. Hopefully this will work on my 1998 Avalon XLS, 7 speakers. I think it has a factory amp too. Will the amp work if I just connect the wire harness to the factory wires? I am thinking of running the amp kit (power, ground and RCA) wires to the trunk too. Just in case I want to add a separate sub & amp in the future.

Although, I am happy with the factory sounds, but the factory stereo is missing some buttons (to change the radio channels) and the factory HU doesn't have mp3 and ipod ready. The reason I want to replace the HU because I want the same sound (or better) with mp3/ipod ready compatibility.

Overall, I love this Avalon (I just sold my Lexus IS350 because it's too tiny for my two little boys).

Crutchfield will send you this harness (http://www.crutchfield.com/p_120708112/Toyota-Lexus-Wiring-Harness.html) if you filled out your vehicle info correctly. You just splice the black, yellow, red, and blue bare wires on the Pioneer harness to the black, yellow, red, and 2-blue-together wires on the separate harness from the link that they send you. That harness has 4 RCA cables that you plug directly into the RCA outs on the Pioneer head unit. You will have 8 extra bare wires on the Pioneer harness that you do not use (for cars without amps), so just wrap those in electrical tape or heat-shrink tubing. Mine had the illumination wire too, but other than that yours will look like this:



The Avalon head unit is really easy to get to because the bezel comes off without much force and without breaking, so you can always just install this head unit, then worry later about running wires to the trunk. You'd just need to throw on 2 RCA splitters for the pre-outs and then directly splice into the power and amp turn-on wires (just ground locally in the trunk) and run the 2 wires and 2 interconnects if and when you decide to throw in a sub amp. I'd just wait to do anything until I had the amp in hand, since taking the head unit back out to access the wires is quick.

I just realized I never updated after installing my build for the Avalon. I'll have to get permission to post pics of it installed, but here's what the single DIN ipod dock looks like wired with the auxiliary charger and head unit:

 

Hi all,
I am happy to share that I've successfully installed the new pioneer stereo in my 98 avalon xls. It sounds much better than stock HU. However, the factory sub raffle when i turn up loud or if there are too much bass.

Is there a fix? or I'll have to live with it.

 

I have no experience with subs, but I'd imagine you could add an in-line volume/level control just to the sub, or simply a resistor. Although it may be that you need to lower the signal so much to stop the rattle that there's no point in having the sub hooked up at all. Personally I'd replace it or disconnect it.

On a somewhat related note, does anyone know the part number of the hex/philips head flange bolts/screws that hold the head unit into the dash? Not the short screws that attach the head unit to the side brackets, the 4 screws that attach the brackets to the dash. The only parts image I can find has a bolt with a nut, and it also only has a single-din stereo and therefor the side brackets are different, so I'm not sure if 90159-50238 is right:

It's the four circled screws/bolts here:
.

Alternately, since I don't have access to the car (until I go to replace the missing screw), if anyone knows the dimensions of the bolt (length, pitch and # ?), I could get a similar one from Lowe's. I know it's a long shot, but I just thought I'd put that out there. Thanks!

 

I had a Pioneer Head unit installed May 2010 at Best Buy. I get in the car to drive home, and I hear a buzzing noise. Like a dentist drill whenever I am on the accelerator. I immediately call Best Buy and the dude says it's my amp, and it needs replaced. I didn't believe him, I'm nowhere close to a car or audio guru, but my room mate was and he said it couldn't be that.

i did some research online and found people saying if you switch out the head units with engine connected you could blow a tiny fuse in the Head unit(Pico fuse). So I drove around with the noise for a year. Sometimes, depending on the song you didn't hear it. But when you heard it, it's annoying. So in April my wonderful fiance decided to try to get it fixed because she's awesome. She scheduled me an appointment to take Ava into a new local car audio place to have them fix her up. The guy sits in my car for a minute and says there's nothing wrong, and I'm making it up. She a crappy employee!

So I leave with the noise STILL....I go to another car audio place in town and tell them about the pico fuse I read about online and hot swapping....the guy laughed and said in all his years installing head units and stuff he never disconnected an engine, he says it's my grounding of the head unit.....

So, now I want to get to the bottom of this, and i am wondering where you guys ground your units? If yours works, mine must!

 

Good grounding is a must on any audio system. If need be, run a dedicated ground from the radio to the amp, and even battery negative.

What you're hearing is alternator whine.

Pioneers have an issue where the RCA ground, (assuming you're running line level from the headunit) is not grounded to the chassis. The quick and dirty fix is to do this:

I assume you're using the line outs of the pioneer with the interface harness to use the oem toyota amplifier.