tacurt

I cant figure out my why a/c isnt working. The compressor will not kick on. The dash light comes on, fuse intact, and the pressure is good. Also ran a jumper to the compressor and it kicked on and got cold, so the clutch and compressor is good. I have no power going to the wire that hooks to the compressor, checked it with a meter. I know, roll down the windows. Thats fine when I'm by myself, but I don't like the wind on my 15 month old while he with me. What can I check next to see why theres no power to kick on the compressor?

DCYota

Have you checked the entire length of wire and the ground? If you know there's no power getting to the wire itself, then you know where to start

tacurt

The wire runs into a large bundle of wrapped wires. I was going to wait until I exhausted other options before I started unwrapping wire bundles. Does the a/c system have a pressure switch somewhere, I know it won't come on if the pressure is low. I thought there may be something else relatively simple I was missing.

tacurt

Searched again, so it does have a low pressure switch. Question is is it behind the glove box or in front of radiator, read both. Also is there a relay somewhere?

DCYota

http://personal.utulsa.edu/~nathan-buchanan/93fsm/

This is going to be your best friend for a while. All your questions are answered within

mt_goat

Another thing to check, on the 3.0 4x4 auto tranny models there is a coolant temp switch, that is meant to shut down the AC if the coolant temp gets too hot. It is located behind the glove box on my truck (or maybe it was the relay for it). Actually mine is bypassed now due to my 3.4 swap (the 3.4 models don't use that switch).

In that same area behind the glove box, there is an adjustment screw that sets what rpm the AC comes on at. If turned all the way down the AC will still run at idle (that's where mine is set).

4mydogs

Is there a way to bypass this? My 4Runner isn't overheating, but whenever the temp gauge climbs even slightly higher the A/C shuts off.

mt_goat

Yeah the AC shop I had convert my system to R134 found a way to by pass it. I think they just used a jumper wire to by pass the relay. I'll see if I can find a pic later. Be aware that just because your temp gauge shows normal doesn't mean your temps aren't hot. My factory temp gauge shows normal (smack dab in the middle) all the way to 240 degrees F. If your's is showing anything higher than normal my guess is it over 240 F which is too hot IMHO. I'd be very carefull running the AC while your cooling system is already stressed, especially with an engine prone to blowing head gaskets.

mt_goat

This MAYbe the relay, but not sure:

4mydogs

Thanks, and thanks for the photo. Other than installing a "real" temp gauge with actual numbers, is there any other way to tell if the engine is actually running hot? I'm not losing any coolant, and it isn't boiling over.

mt_goat

If you had OBDII you could use a scanner like this:
http://www.urdusa.com/product_info.p...s_id=840100000

But I guess you have OBDI right?

Some guys have used those handheld temp guns to check.