a/c compressor not engaging 03 corolla

[cupidstoy]

hey all!

wife's a/c quit working a few days ago. i was out of town and just had time to do a bit of troubleshooting. thought i would ask for help to see if there is a common problem that might be the cause.

car has 106,000 miles. when the a/c button is pushed, the a/c light on the dash switch comes on and the engine revs up a few hundred rpms like normal, but the compressor clutch does not engage to spin the compressor. i have checked the fuse under the dash and it is ok.

does this mean the compressor clutch is faulty or could there be something else (a cut out switch or similar faulty part) that may be causing the problem? no check engine light or any other problems i could find.

thanks in advance. if you guys don't come up with anything i'll have to take it in to the dealer as the outside temps are heating up!

[cupidstoy]

update:

relay checks out. i swapped the horn relay with a/c relay and horn honked. i also tried jumping the relay large pins and still no compressor action.

that leaves: wiring harnes, compressor clutch, hi/low pressure switch, or a leak causing system to be low on coolant causing hi/low switch to cut out compressor for safety.

i don't have gauges to check the pressure so i'm at a dead end. the car is going in to toyota dealer on tuesday next week. they think they can troubleshoot it for 1/2 hour of labor (35 bucks) and give us a report on their diagnosis.

if anybody has other ideas, common problems with the 2003 corolla a/c system or basically any way to confirm the dealer's diagnosis it would be mucho appreciated! i'm guessiing we'll be on the hook for at least many hundreds of dollars once the dealer is through with us, so ideas or confirmation of repairs is always helpful!

thanks.....

toy

[ShoNufFunky]

Did you ever figure out what happened with the AC on your wife's car. My wife also has a 2003 Corolla and appears to have the same issue. I was hoping you can point me in the right direction before I go to the dealership. Any information you can offer is appreciated.

snf

[cupidstoy]

i gave her the choice of me replacing the relay for 40 bucks from the autoparts store w/ no warranty or guarantee of it being fixed, vs. taking it to the dealer. she opted for the dealer who charged her about 200 bucks for a new relay and topping off the refrigerant. problem fixed.

incidentally, i tested the relay we had by swapping with the horn relay. they appear to be exactly the same. the horn honked with the a/c relay, so i don't think it was really bad. what i think happened was the refrigerant was just low enough to trigger the low pressure safety switch. when they topped it off, it cleared the condition,.

but that's just my theory.

good luck ;-)

[ShoNufFunky]

Thanks! That helps a lot. I'll start by adding refrigerant.

snf

[cupidstoy]

i should also add the toyota dealer was supposed to add the tracer dye to the system when they charged it. this would enable them to detect the source of the leak should the refrigereant become low again. i think this is a good idea. although the car is now in it's eight year with out a previous leak, it is obvously loosing refrigerant somewhere and this will need to be found and fixed at some point.

perhaps you can do the same thing yourself to make finding the leak easier if that turns out to be the problem. also, i would switch the relay with the horn relay first before adding refrigerant just to rule out the relay as the problem. the two relays are right together and switching them and honking the horn takes less than 5 minutes.

good luck.

[ShoNufFunky]

I wish I'd taken the time to read your posting before I went to the shop. In short, the relay was bad. The problem is that the A/C relay is NOT clearly marked. Its the M/G CLT relay. Not sure what the means but it took the mechanic about 40 minutes to lookup the information on the Internet. Once we figured out which relay controled the A/C we did exactly what you recommended. We whiched the horn and A/C relays.

Now I know. Thanks for all the info. I really do appreciate it.

snf

[cupidstoy]

glad you got it fixed ;-)

fwiw, i think it stands for magnetic clutch. (MG CLT)

another piece of undecipherable acronym speak form our friends in japan!

my truck has the LSB & PV. you know, the ol' Load Sensing, Bypass and Proportioning Valve! part of the rear braking system.

hah!