98 Avalon XLS Trunk Release Problem and Heater/AC Control Problem

[moviegal22]

I have a 1998 Toyota Avalon XLS that has the trunk release button in the glove department rather than the side of the driver seat, but doesn't open when I push it. The fuse is okay and doesn't seem to be the problem. Does anybody know how to fix the problem? I also have a problem with the heater/ac control unit that is mounted below the radio with push buttons. When I turn the temperature knob all the way to the left to cool, cool air and ac would work, but if I turn it a tiny bit to the right hot air would come out. Does anybody know how to fix this or do I need to replace the unit itself?? Please HELP! Thanks.

[swiftjustice]

When you push the trunk release button, do you hear the solenoid in the trunk click? (that is what actuates the lock release) Can you open the trunk with the button on the remote (not using the key)?

If the solenoid is getting power, then you should hear the obvious click of it trying to kick open the lock. If you don't hear the click of the solenoid, then check the fuse for that circuit or the connections to the solenoid itself in the trunk. If you can confirm that power is actually getting to the solenoid (an ohm meter or a cheap 12V test light from harbor freight will confirm this) but the solenoid is not working, then the solenoid itself has likely given up the ghost.

If you do hear the solenoid working but it is not kicking the lock open, then either the lock or solenoid is worn such that it is no longer kicking it open all the way/enough to actually open the lock. The solenoid itself might need to have its position adjusted slightly or be replaced, or the lock mechanism itself may be worn or broken where the solenoid actuator contacts it.


On the heater issue, I'm assuming that you have the auto climate control setup. Don't really know there, except the system operates a valve for the heater. Don't know if there is an adjustment or not - but I see used control units on E-bay all the time for a fairly reasonable price.

[moviegal22]

I couldn't hear any click when I press on the trunk release button. I couldn't find a fuse specifically for the trunk. I looked at the fuse inside the car and underneath the hood and didn't see one for it. Is there a specific fuse that is linked to the trunk?

[cexsiman]

+1 i love harbor freight. i just picked up an ohm meter on tuesday for $3 !!! i dont have an electronic trunk release. but i would first worry about the solenoid engaging before anyting, Except for if the lock is working correctly.

[swiftjustice]

I don't have a FSM or a wiring diagram, just the owner's manual, so can't conclusively trace which circuit its on. Looking at the owner's manual, likely suspects could be fuse #7 in the engine fuse box, or 27 or 29 in the interior fuse block.

You may just want to pull all the fuses and look for blown ones anyway.

If all the fuses look good - go to the trunk to verify that power is getting to the solenoid or that its even still connected. Find the solenoid (you'll need to remove some of the trunk lining), I believe the solenoid is in the trunk lid itself. Use the test light to verify that its getting power. If it is, and the solenoid is not working, the solenoid is toast.

[moviegal22]

Originally Posted by swiftjustice

On the heater issue, I'm assuming that you have the auto climate control setup. Don't really know there, except the system operates a valve for the heater. Don't know if there is an adjustment or not - but I see used control units on E-bay all the time for a fairly reasonable price.

I replaced the climate control unit and it didn't seem to solve the problem. Does anybody have an answer to how to fix this problem?? When I turn the knob all the way to the left cool air would come out, but when turn just a tiny bit to the right it comes out hot air from that point on.

[swiftjustice]

Assuming the control unit itself is good, there are other possible areas of fault; the servo motor or the water valve itself, or the sensor for the auto climate control unit.

The servo motor is a little electric motor inside the dash near the heater core, when you actually move the rotary knob it sends a signal to the motor which operates a cable that opens and closes the water valve.

The water valve is simply an inline valve in a hose in the car's coolant system that opens or closes to let hot water into the heater core.

The water valve can be replaced through the engine compartment and is easy to do if that's the problem. Not so sure about the servo motor if that is the problem.

You may want to operate the temp control switch and have someone watch the water valve in the engine compartment to see how much the valve is operating, if at all.

[cexsiman]

i discovered the heater valve while doing my intake a day or so ago. it is on the firewall in the middle (almost center of it). there are two 'hoses' coming out and one has a black square, with a small cable going to a valve on it. i'm pretty positive that its a cable operated mechanism and there is no motor (or electrical) issues to deal with.

look at my intake install pics i just posted and you should be able to see it. (They might not be working, idk photobucket has been giving me troubles)
but they are the only hoses in that location. it might be the cause of your heat issues.

[swiftjustice]

You can see the valve in Cexsiman's last posted photo, its just above the brake MC reservoir in that pic. (would be to the left of it if actually looking at the car)

The valve itself does not have any electrical connections, the valve opening/closing is provided by the electrical servo motor (which operates the cable) which is inside buried near the heater core itself.

Since that setup is the same as the Gen3 Camry, you might search that forum also for any threads on the topic, i.e. how to diagnose if its the valve or the servo motor thats the problem.

[Elad]

I have same problem on my 97 xls I just got a few weeks ago. Its either cold or hot
The servo moves completely on or off, will not incrediment.
The servo is located on drivers side of the a/c heater core box (near gas pedal)
I so far not been able to remove the servo do to a vertical metal bracket in the way of the last screw
I tore my dash apart looking for this bugger. You will need to remove the lower paned below the radio/controller panel to see it.
I even remove the fan blower as had vibrations at full speed. Found some acorn shells in the blower wheel. Cleaned n replaced, now that problem is fixed

I was hoping for an answer here as like Moviegal22, mine too moves at the 65^ setting on the temp dial to either full heat or a/c if below.

It won't be the water valve as the servo is not stopping at partical positions/setting of control.
It (servo) also operates a lever in the a/c-heater box too besides cable to valve.

If you changed your temp controller, then it must be the servo acting up by not sending its pulses to the controller. I even tore my controller apart taking a peek...
I found a control unit for $50 at a auto salvage place and will be go there next week to try it there in the parking before I leave... Thanks for that info that didn't solved your problem, I'll try before I buy by leaving my dash panels torn apart for a quick test...
Also seen used controllers for $80 on ebay few days ago.

If replacing the controller didn't work, then would also be easy to get another servo and connect the plug to it (without mounting) to see if it works and moves only a little, not all the way/temp settings. Thats my next step if controller is not the prob.

Tomorrow I shall see how to remove that vertical post bracket and probably get another sheetmetal scar in the process as I did today on the forearm

[moviegal22]

Can you send me a picture of what the servo looks like??

[Elad]

O,o... Picture typo (servo*)
The white plug comes out easy - but there is a locking tab on the plug.
I also removed the panel under steering wheel.
Let me try a control unit tomorrow before you go tackling the servo.

[Elad]

HOLD THE PHONE
I found the answer, but after 4 hrs in the auto salvage yard under a hot sun to boot
I removed & replaced the used salvaged $50 control unit..... Failed
Then I removed the servo ($15) from a smashed up car and believe me, it was not a party doing so and yes, more blood spilt trying
I connected the servo it to my connector... Test Failed
Ok, now am Hot & stumped.... But at least I not paid for parts yet anyway, just a lot of hard work trying to fix
Still thinking as to how much this is going to cost to get fixed at the dealer I began wondering
as to why there are small slits in the cover panel by the ignition key
There is a small connector with 1 electronic part inside of it.
It turns out to be a solid state theromstat resistor I suppose.
Another walk back again a 3rd time to the salvage car back 3/4mile deep, I got this part and put it in my car and tested again....
Y A H O O Thats all it was.....Everything works now

Right in the middle of the picture next to the ignition key is the faulty part.
Housed inside a black connector is the bugger
They still charged $15 for it, must be a minimium charge....
Just looking online, they sell this thermister for $8.05c at 'discounttoyotaparts com' (see body parts/Air conditioner & heater/Thermister)
but who knows shipping chages. Anyway I am so glad this works, so no biggie...
A simple proceedure to replace, compared to the servo... (Glad I didn't have to replace the servo ($114 new) as that would be a
hugh challenge to get at.
I was able to bend some things to get it out, but installing a servo would be vary hard to do).
So there you go... I done the hard work for both of us and anyone else who runs into the same problem...
Must not be any technicians working over these forums as he would of known right away

[swiftjustice]

Yup, the temp sensor for the auto climate control, mentioned in my post of 6/18 as one of the areas of potential fault (along with the water valve and servo)

[moviegal22]

Right in the middle of the picture next to the ignition key is the faulty part.
Housed inside a black connector is the bugger

I can't seem to see that part. Where exactly is it by the ignition? I don't see anything like that next to the ignition, but I do see that empty retangle slot but looking inside it I don't see anything that looks like what I see on your picture.