A/C not working, clutch not engaging Options

[celicamike]

Hey guys, I'm hoping you can help me with this problem. I noticed that my A/C wasn't working, and discovered that the magnetic clutch does not engage when I press the button inside the cabin, even though the light comes on. So I got my digital voltmeter out and checked the wire going to the compressor. There is no voltage going to the compressor with the A/C button on or off, so I suspect a fuse or wiring problem. Do you know where the fuse is for this circuit? Have any of you experienced this problem before? I appreciate any help. Thanks

[stephen_lee]

i belive the fuse is AC in the engine bay

[soulshadow]

If the fuse doesn't solve it, take the belt off of it and try to turn the clutch by hand along with the pulley. If its stuck and doesnt move your AC is broken.

[trdproven]

Timing would be a problem if the ac clutch only engages sometimes like it gets warm when the idle doesn't kick in the clutch but I dont think that is the case here. I can think of the actual AC switch could be bad. BUUTTTTTT, From my experience I've seen the transistor as the culprit usually < this controls your fan switch which engages your ac. Way to know also is that your high settings on your fan stop working so you use medium and then low until it eventually doesn't work. I'm pretty confident that your transistor is bad. You can also idle your car and open your hood and listen for the clicks from the AC clutch but I doubt you can hear this if you can't even get the switch to work at all. If all toyotas are right, the transistor is under the dash of the passenger side, its pretty small. In general check your AC switch, fuses, transistor (could be burnt or seperated just like a fuse), and besides that we can get deeper into discussion later after you check them.

[celicamike]

Thanks for the advice fellas, I'll start by checking the fuse. You say that its in the engine compartment, but which fuse is it? Is it labelled or anything? How do I know if its bad?

[trdproven]

Tell us your symptoms, read my post and tell me if I hit any.

[celicamike]

Timing would be a problem if the ac clutch only engages sometimes like it gets warm when the idle doesn't kick in the clutch but I dont think that is the case here. I can think of the actual AC switch could be bad. BUUTTTTTT, From my experience I've seen the transistor as the culprit usually < this controls your fan switch which engages your ac. Way to know also is that your high settings on your fan stop working so you use medium and then low until it eventually doesn't work. I'm pretty confident that your transistor is bad. You can also idle your car and open your hood and listen for the clicks from the AC clutch but I doubt you can hear this if you can't even get the switch to work at all. If all toyotas are right, the transistor is under the dash of the passenger side, its pretty small. In general check your AC switch, fuses, transistor (could be burnt or seperated just like a fuse), and besides that we can get deeper into discussion later after you check them.

OK, so I have an update. I checked all the fuses and they are good. I also tested the compressor by connecting it directly to the positive battery terminal and it engages just fine with 12 volts. For some reason, the compressor isn't recieving voltage when I press the A/C button, even though the button lights up. You mentioned that the transistor could be the problem, although my fan works fine, even on the high settings. I want to check my transistor, but I don't know where to look. You say its under the passenger dash, but could you be more specific? Also, how do I know if its bad? Thanks.

[stephen_lee]

i believe hes talking about a transistor in the A/C amplifier. that would be behind your glove compartment. look to the left of the blower motor and it'll be under a white cover.

[trdproven]

^ Right, transistor has more than one link, I think three and as they die one by one there goes your AC. Did you try another AC button? Also, your compressor can be fine, but it is useless if the AC Clutch is not engaging. AC Clutch is activated and also controlled with idle and timing on your car, if you cars timing is bad, it won't engage your AC clutch consistently if any at all and you would get cold, then hot and then cold when you accel and then hot when in idle again, etc. When you press your AC button you should hear a click from the AC Clutch if it activated. Other than that you have a leak in your line, condensor, evaporator, dryer, no freon, leak at your refill valve. Honestly, check your freon charge, if it is low - then put some in you can buy it at the store, test your AC, if it is working there you go you now have an idea that your AC does work now what next? now you can also get a leak tester and just scan around the AC lines and the parts I mentioned. Dude there can also be electrical issues with your AC Clutch. Ahhh, theres many things you can check.

This post has been edited by trdproven: Mar 21, 2009 - 10:52 AM

[celicamike]

^ Other than that you have a leak in your line, condensor, evaporator, dryer, no freon, leak at your refill valve. Honestly, check your freon charge, if it is low - then put some in you can buy it at the store, test your AC, if it is working there you go you now have an idea that your AC does work now what next? now you can also get a leak tester and just scan around the AC lines and the parts I mentioned.

Yep, that was it. Turns out I had a leak in my AC condensor. Got it fixed and recharged with refrigerant and it's blowing ice cold, just in time for summer . I guess there's some sensor that keeps the clutch from engaging when the AC lines lose pressure. Anyway, thanks for the help; also, anyone who experiences similar problems should definitely do a pressure test.

[trdproven]

Good to hear - a leak tester works wonders with the AC system.