Expert: Candido Figueroa - 8/14/2009

Question
Wife was driving, everything was fine,till nice cold a/c turned hot in a matter of seconds.



Found the compressor wouldn't engage. First checked the freon with gauges and it was normal at about 100 static psi. Next checked all the fuses and relays and they were okay. Did a jump on the compressor relay and it did turn on (as did the cooling fans in a couple minutes) So power doesn't seem to be the issue.



Replaced the transducer figuring that had to be it with everything else checking out. Nope, still wont work.



Went ahead again and jumped the relay let it run for a couple minutes and it tested out at 45 psi the air got semi-cool but not cold. Noticed the low side a/c lines were semi cold to the touch.



Seems to be a blockage of some kind that won't let the freon cycle thru the system. If the drier or expansion valve got clogged I'm wondering where would the debris come from. My next thought was to replace those two items but it's a lot of work if there's another cause to this. What do you think I should check out?

   Thank You for your time

Answer
Hi Blaine

you have two things that control the compressor.  You've eliminated the transducer.  Now check the thermo sensor located at the evaporator case.  Look under the glove box and you will see a little circle with wires coming from them.  That is the thermo sensor.  The debris if any (which I don't think you have) may be from the drier silica.  Check the senor and let me know.