how would i know if the ac switch in the dash is bad everything works except the ac and i was messin around today and if you take and jump the bluish wire in the plug behind the switch the compressor will come on, im not really great at this electrical stuff so if anybody has any ideas im open to hear em.

 

i've put two cans in it and when i jump it the air is cold. other wise there is no oily lines or anything like that

 

low presure switch

 

The computer turns the compressor on. The purple wire is a trigger for it.

If the pressure isn't right or theres a bad sender then it wont operate.

 

I'm guessing you and I are having similar problems.

My AC cut out about four years ago -- yeah, a long time -- but I finally got around to fixing it.

I loaded up the refrigerant, checked the pressure, no leaks. When I went to test out the AC, the compressor clutch doesn't engage. Here's what I've tried:

I've tested the voltage across the connector, and I get zero.

I've checked the fuses for the AC, they test fine.

I've jumped the clutch directly from the battery, and that powers the compressor fine.

I've tested the in-line diode between the connector and the relay, and the diode functions fine.

I've swapped power relays to test the relay, and the car starts fine.

So, I'm at a loss here... what should I try looking for now?

 

ok got around to messing aroung with it a lil today i jumped the relay and unpluged the low pressure switches and the compressor cuts off. dont know if it means anything or not, just a thought. i took the truck to the shop the other day to get it alighned and had them check the system out and its supposed to be charged, all i got from them was that its an electrical problem.

 

ok finally got around to checkin my stuff out the other day. i started lookin and the wiring for the ac looked like it was put in seperate from the rest of the wiring, all the fuses are outside of the boxes and one or two other lil things. but anyway i started lookin and pulled the control panel out and checked to see if everything was good back there. then i saw the lil gray wire running off to the left and then it hit me: that lil gray wire with the 75 amp fuse that i had tucked up outta the way when i got the truck was needed for the ac to turn on. hooked it to the fuse box and the ac is good. really nice and cold.

 

Really hope that 75 is a typo.


Glad to hear you figured it out. I had no idea it wasn't a factory option.