A/C and compressor problem

[GMCJason]

Hey all, I've got a problem with my A/C in my Jimmy. First, it's not cold but that maybe coolant charge problem. The bigger issue is that the A/C compressor engages and disengages about every 3 seconds. When it gets warmed up it's enough to cause a noticeable surge when idling in gear.

The other part of the puzzle is that a couple years ago the in-cab controls smoked a bit. There was obviously a problem but I didn't think too much of it because all the functions seemed to work. Later on it did seem that the A/C was always on as long as the unit wasn't off...for instance the vent air seemed to cold just to be vent air.

Any ideas? I'd like to get the compressor and idle surge problem taken care of but not sure where to begin. Could the surging be related to a malfunction in the controls, like it thinks the A/C is on? Even if it did would it have that much of an effect on idle speed?

Thanks for any input.

 

[5280k5]

Hey Jason, it sounds like the system is low charged and the low side cycle switch is what is causing the compressor to jump on/off. Typically the low side switch cuts out around 26-29 psi so as soon as your compressor kicks on the low side drops below this pressure due to the low charge. As the "static" pressure of the system rises back up with the compressor off the low side cycle switch closes again and the whole process starts over again.

The smoke in the dash Could've been from the blower switch or the A/C switch mounted to the heater control? May have to take out the control and visually inspect for burn marks or possible wire problem at the harness connector side.

Let me know if you got any ?? Or give me a call (303)520-6324

 

[pauly383]

I would think the cycling on and off would be low freon .

The controls I wouldn't know , maybe a bad or dirty switch . Power touched ground .

 

[GMCJason]

Thanks guys. I kind of suspected that the low charge was responsible for something. I'll get that taken care of but wanted to see if there was something else that could be part of the problem and should be fixed before it's recharged.

I'll pull the controls out soon and see what it looks like in there.

 

[pauly383]

One thing could add about controls . Mine stopped working once . Found the plastic housing the levers move to do the switching at the same time the cables move has a pin through it that got old and broke , allowing my switch to just not work . I fixed it with a flathead bolt and nut .

Probably not related , but I was proud of myself for fixing it .