AC question

[ripewithdecay]

I just got a 97 pickup recently and i was trying to figure out a starting point on diagnosing my A/C problem. Currently when i push the a/c button in, the light doesn't come on, neither does the compressor. (The blower fan is functioning) Would a faulty relay cause the light not to come on? Also how can i check the relays? Thanks!

[longtooth]

Start with checking your fuses.

[ripewithdecay]

all were checked and good

[longtooth]

I would then check the pressures and see if you can by-pass the cycling switch.

[RT22]

POP the switch out use ohm meter to make sure it is working, if the light is not coming on could be bad switch or lost power to the switch. If you are not sure how to check with meter post back I will check back and try and help

[mrecoolgar]

Pull connector from pressure switch, behind coolant overflow on 2.4.
Use paperclip oto connect both female terminals.
Compressor will run regardless of pressure.
Will not cycle on if faulty.

[Q451990]

Not entirely true. The compressor gets it's signal from the ECU, so you have to have three different conditions correct to get the ECU to send voltage (or ground?) to the compressor...

-Dual pressure switch is in range (pressure not too low or too high)
-freeze up sensor on evaporator is reading within range
-overheat sensor on compressor is closed (hasn't overheated)

Pretty sure you'd jump out the a/c compressor relay to see if it works... I had to do this to start the charging process on my '97 after replacing the evaporator. Check the factory service manual for all of the diagnostics... www.nicoclub.com/FSM/

Heath

[ripewithdecay]

sorry for not posting back sooner. I will try all suggestions and report what I find, thanks!