My ac been acting a bit skittish lately. Here are the symptoms (already replaced the AC relay so that is out the equation.)



The aux fan stays on (turns off when the car is turned off).
The AC compressor doesnt engage, but it's not locked up.
The system holds pressure, but still the AC clutch wont kick in.
Had it checked for leaks with that dye stuff and it came up clear.
No leaks, no overheating, no odd noises.

Air blows though the side vents, but not the center (The main center vent seems to be stuck closed and the bar is not connected.) While at the same time air is coming out the defrost vent too. (I personally dont care where the air comes out as long as it is cold.)

All functions on the control unit work as intended except no ac (even the climate control work and blower motor adjust according to temp.)

ANyone every had this problem or know what's going on?


And is it possible to just simplify the system by running the clutch to a simple on and off switch? I dont care about heat as who needs heat blowing in the desert.


and I forgot to add the aux fan is turning at the high speed setting. So help me out here. dont give me the silent treatment.

 

I battled with mine this week. No compressor clutch kicking in and I had pressure in the system. One of my blue red wires connector was corroded internally on the low pressure switch on the left side of the rad behind the headlight. I have a few more tests I can post later if you need.

 

You should be able to jump the low pressure switch to see if the compressor engages. If it does, pull the jumper off. Test the switch for continuity. Or do the continuity test first. Your call.

If the switch is bad, well, replace it. If not, check the wiring and connections. maybe all you need to do is clean them from corrosion.

 

Test #1: Testing voltage supply for AC control unit. Remove AC control unit and hook up a volt meter positive to terminal 5 and neg to 1. You should have battery voltage when you turn the key on to position 2.

Test#2 : testing control voltage for Ac compressor from low pressure switch to control unit, Ac compressor cut out. Positive lead to # 5 and negative to socket 10 should have battery voltage.

Test # 3: Testing AC compressor clutch and wiring. If you jump terminals 5 and 7 with your AC relay removed the compressor it should engage. Start engine breifly and watch if the compressor engages.