I just got an 83 4 x 4 pickup. The A/C system will not send power to the compressor clutch. The unit is properly charged and all the components seem to check out OK. It will blow cold if I jump the compressor clutch. The truck has had extensive engine mods (2 Mikuni side draft carbs). It all looks to be done very well. Is there some interaction between the emisson control and A/C control that could have been changed? Any ideas?

 

Sorry, no clue about your AC problem, just wanted to say awesome truck!

 

My AC system does not interact with the emission system and I don't think the later models do either.

I would start by checking the fuses, then I would check the AC switch to make sure it is working properly (continuity when the switch is on).

Then check all of the connectors in the AC wiring harness (make sure they are hooked up, good contact, etc). Also make sure none of the wires in the system are damaged.

Next I would check the thermistor (sits on top of the evaporator box under the dash). This sends a signal to the AC 'computer' (the FSM calls it an 'idle stabilizing amplifier')that controls when the AC kicks on and off. When the temperature goes below a certain point it shuts of the compressor. When the temperature comes back up it kicks the compressor back on. Its fairly easy to test - the procedure is spelled out in the FSM.

There is a pressure switch in the system, but I don't think that is your problem if the air blows cold when you jump the compressor.

One other thing you might try: there is a knob on the AC computer (the computer sits in a slot on the bottom right side of the evaporator) that controls the idle speed at which the compressor kicks on. I'm not sure how high you can set it, but you could try turning it down.

If none of these solve the problem, I would try to get ahold of another computer and swap out computers.

 

I tested all that almost line for line. Thanks for the ideas. It is probably something stupid like a loose harness connection.

 

Here's a couple of links that might help.

Look at post # 234 http://board.marlincrawler.com/index...9954#msg879954

here's another
http://board.marlincrawler.com/index...9149#msg879149

Lemme know if you need more help, glad to....

 

well that truck aint worth anything no sense in keeping it but i would galdly take it off your hands . very nice

 

That is a sweet truck!

 

Nice truck! Wish I had AC on my '83.

 

Very nice looking truck. The A/C on my 83 works best in 5th gear, downhill. 2/55 A/C in mine, and it doesn't look half as good as yours. Hope you find the issue.

Fishhook