Ok i dont know if i am missing something, but i just changed my A/C evporator, after installing new one i evacuted the system and am holding vaccuum, but when i put the jumper wire oi the low pressure switch the A/C compressor does not kick on. I have checked all wiring and I dont see any i failed to reconnect, any ideas, it was working fine prior to changing the evaporator other than low air flow volume, which is why it was replaced, it was clogged up abot 70%. There is no power to the low pressure cut off switch plug on the compressor. i just did a continuity test on the high pressure cut off on the accumulator and it is closed/activated, and should be open, can i reset it. i added refridgerant anyway a suggestion from a mechanic friend of mine, and i am assuming this is what is causung the high pressure to trigger, i pulled it off and check for open/closed and it was open, so i pluged it in and tried to jump the compressor again and still no power.

 

i had this problem and just figured out why mine wouldnt turn on, can you get the compressor to run if you jump it but connecting it to the battery?

 

no i havent tried going directly to the battery yet, i unhooked my battery to reset the computer, i had to turn on ignition key while everything was still loose to put truck in nuetral and roll it back, i dropped one of the orings for the new evap, i figured i might have put a code in it, but i will try it here in a few minutes. and get back to you.

 

alright, i dont remember exactly how it went cause my dad did it, but you just unplug the cable in the front of the compressor and get to 2 wires and hook one side to the batter and make sure you remember what cable is + and - and only connect to the wires to the compressor inside where the plug went (there should be 2 metal things inside)

 

like a jumper wire, i tried that with no results

 

hmmmm, no sign of life at all? did you have the car running?

 

yeah it was running, funny thing is that other than limited airflow through the system yesterday it was fine, i filled it with freon about 2 weeks ago and had to use a jumper to get the compressor going, i am at a loss right now.

 

did the compressor make a weird rattling noise or sound unusually noisy when it did run?

 

it did when i first turned on the a/c for about 2 minutes but quiet other than normal afterwards.

 

well from personal experience when the compressor makes rattling noises and is just plain loud that usually indicates that the compressor is on its death bed