98 avalon a/c system short - Toyota Nation Forum : Toyota Car and Truck Forums

ezwingert · 08-02-2007, 03:52 PM

Hi guys,

Was driving down the interstate today and the A/C suddenly just went out (in 93 degree South Florida--that is just a bit a problem!), Also blower out and no rear defooger. Found the 10A fuse in the passenger compartment was blown. Replaced same and it blew right away. Replaced the fuse again with A/C off this time and heater, blower, etc. it works just fine. Turned the A/C on again and, yup, you guessed it, it blew again.

Seems like the problem is narrowed down but I don't have clue as to what I just narrowed down to. Can any of you help? Thanks.

Erich

***toyomoho*** · 08-02-2007, 04:34 PM

What is the name of the fuse?

This fuse may go to A/C, rear window defogger and mirror heater. Could be a short in the wiring to any of these components.

Check the A/C compressors magnetic clutch for problems. There should be a power plug on the compressor, unplug and see if the fuse still blows.

ezwingert · 08-02-2007, 05:03 PM

The fuse is the mini 10A named "Heater" in the small fuse box by the driver's side door.

The defogger worked fine when the a/c was off when I tried the heater/blower by itself. Do not have a mirror heater.

I will go try to unplug the compressot and see what happens. Back in a few.

Erich

ezwingert · 08-02-2007, 05:18 PM

Can't unplug compressor yet. Engine too hot to handle. (Went to the grocery store for the wife). I'll try again in a little while.

ezwingert · 08-02-2007, 06:33 PM

Can't get to the connections for the compressor without taking the alternator out, whihc of course involves a bunch else. Is there any way to unplug the compressor from elsewhere?

Is it possible the a/c switch in the dash might be the problem?

Erich

***toyomoho*** · 08-02-2007, 07:22 PM

From what I can tell, the Heater fuse goes to A/C system and rear window defogger. The compressor clutch is controlled by a relay. It may be possible to pull the A/C clutch relay (MG CLT). The relay might be located in the engine compartment relay box (plastic box) on the drivers side next to the inner fender wheel. The relay may be labeled or look on the inside of the top of the box for info.

Do not have an Avalon wiring diagram, suggest using the Generation 4 Camry (with V6) with the automatic A/C system. The two cars are almost the same.

Might be the clutch has a short or the compressor has a problem. Or maybe a relay has a problem. You can also download info on the A/C system.

If you can't find the Gen 4 data, try the Gen 3 wiring info.

http://oregonstate.edu/~tongt/camry

Or try the library, the often have manuals.

10 amps is a lot, not sure the dash switch would cause this unless a wire came off and caused a direct short. The system components that draw a lot of current are controlled by relays.

Suggest you try operating eveything except the A/C to make sure the heater motor, air control doors, etc are working. The fuse goes to more then one A/C circuit and also goes to the A/C control module that controls the temperature requlation in the car.

jon456 · 08-02-2007, 08:19 PM

Your problem may be different, but the same thing happened to me and the blowers didnt work and the ambient temp display didnt work either. My A/C amp needed to be replaced. The toyota dealer wanted 1100 bucks for it, I went somewhere else and got it fixed for $600. Still expensive. I also have a 98 XLS. What a BS problem.

ezwingert · 08-02-2007, 08:49 PM

Thanks Toyomoho. Will check on that stuff tomorrow. You are a great help and I appreciate it!

ezwingert · 08-02-2007, 08:54 PM

Jon456,

Thanks for the response. Mine is an xl. The a/c system is manual so i don't think I have an amp, which I believe is for the auto a/c systems. I could be wrong but I haven't found anything that fits that.

ezwingert · 08-03-2007, 10:00 AM

Toyomoho.

I ran everything on that 10A heater fuse and all worked fine. I pulled the MG CLT relay and turned the a/c switch on and the fuse did not blow. Tried replacing that relay with one I knew worked and the fuse blew again. Sounds like my problem is on the clutch or compressor. What think ye? BTW, the A/C pdf page on that Camrymanuals page you mentioned won't come up for some reason.

***toyomoho*** · 08-03-2007, 01:17 PM

The link to the Gen 4 manuals does not seem to work. Try the Gen 3 A/C info
should be pretty close. Just tried this link and it does work.

The Gen 3 wiring is a little different then the Gen 4. If you need Gen 4 wiring post a private message to me and I can arrange to email it. It is 6.5mb. I don’t have Gen 4 A/C info. If you have the wiring you may be able to run things down based on color code and use a meter to check for shorts.

As you have a manual A/C one more thing to check is Fan Relay No 3. The clutch relay appears to power this relay. This Fan relay turns on/off the radiator fans inconjunction with the compressor going on/off.

Fan Relay No 3 should be located in the same relay box you found the A/C clutch relay.

The clutch could have shorted out or the wiring to it.

georgiatwo · 06-21-2011, 10:29 AM

1998 Toyota Avalon V6 with Manual AC temp. My air has worked beautifully and strong and I dont think it could be a compressor or freon issue. It just went out on Sunday. We were driving over a small ridge and after working wonderful and strong all day, the lights on AC just went out. I pulled over and could smell something burning or getting hot. I marked the pulley and clutch with perm marker to watch it turn to make sure it wasnt locked up and they were both still turning.
I may be wrong but I was thinking that since it has never given me any issues all these years and still blowing strong that it could just be a relay or an electrical issue. This is not intermittant and the control lights are not flashing, they are off. I have been hearing a slight ticking or rattling under hood that goes away when AC control is turned off. 2 weeks ago my Local mechanic said it was the serpentine belt and replaced it. Noise still here. Then after running the AC for a trip (several hours) everything went off- lights to the AC controls, fans and air conditioner. The clutch is still turning fine. Serpentine belt still intact. I checked the 10A fuse close to steering wheel and it was blown. I turned the AC control off and replaced the fuse. I turned the AC control on and it worked for a few seconds and then it blew the fuse. Could this be the magnetic coil for the clutch? It just seems electrical. Because the air has never had any problems or never stopped blowing cold air, it is hard to believe it would be a compressor. Because of the cars age, I dont want to put alot of money into it. I replaced the motor last year and it has almost 200K miles. I simply want to keep it as an extra auto for short drives to store. (Has anyone replaced ONLY the magnetic compressor clutch coil?)