Ac delco compressor will not turn off.

[lanconcj]

My AC Delco compressor will not shut off. My single cab 86 gets cold fast so I switch the control to the vent periodicly to warm up. I noticed a couple of days ago that on the vent selection I am still getting cold air. This started after I installed a new radio. It is possible that durring the radio instalation that something on the air controller was knocked loose. It is dark here now and the mosquitos are to bad to go out and look so I thought I would look here for advise. Is there a "switch, fuse, relay" that could have gone out causing this problem? In the air off position, I can hear the compressor still on. I have to go to the heat position for it to quit. Tomorrow when the mosquitos are hidding from the heat of the day, I will be able to look closer.

[Desert1957]

I can only think of two things that could cause your problem.

*some type of problem with the dash selector switch or
*the clutch on the compressor , It has an air gap of something like .030
if its gaped too tight it can make its own magnetic field causing it to stay engaged.

Some if the older A6 style compressors use to have a small diode installed at the wiring plug near the clutch to prevent this situation.

I would check it for voltage while the engine is turned off and when its on vent, should not have voltage at either time.

Desert

[Slonaker]

I had that problem on my '86. Replacing the dash control fixed it.

Slonaker