I have a 1993 Dakota, manual trans with 3.9 Litre engine.I can't get the A/c to come onunless I bypass the a/c relay, then I get ice cold air from the vents. When I bought the truck I had to do a lot of electricle repair and I don't feel like chasing down yet another bug in the wiring just for A/C, so I was wondering If I could run a new circuit with a toggle switch. Has anyone tried this? What would be the best way to go about it? Any ideas/information would be greatly appreciated.

 

One of your pressure switches is having an issue. Shouldn't be hard to figure out which one.

 

Ok well I found the one by the firewall bypassed it no change. Couldn't find a second one traced the pipes no luck. The one I found seems to run straight to the pcm.is there another pressure switch? If so where is it? Thank for the reply btw.

 

There should be two.... the other one might be on the compressor itself, if you didn't find it on the lines.

 

Ok so then how do I test it? Or alternatively can I run a new circuit with a toggle switch?

 

Bypass each switch individually. If the a/c starts working, you have a good idea where to start.

Wouldn't hurt putting gauges on it, and see what pressures look like......

 

I'll check the pressures tonight. Thank for the replies.

 

Almost forgot. Any idea what the pressures should be?

 

Depends on the weather. Should be a chart out there on the web somewhere that relates temp, to likely pressures.

 

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