1987 C4 25969

I have a 1987 Corvette that has the automatic temp control for the heater and AC.
I select the off button and the system AC keeps running.
What is usually the cause of this problem.
Thanks

MK 82

Clean the contacts for the button.

Dads90

A few things to try. Try pushing any other buttons and then shut off car. Then restart. Or try this with just the key in the on position (not running) and finally, try disconnecting the battery for a moment. Mine did this a time or two and a restart seemed to resolve it.

IRAraid

I have a '95 with manual (C60) control and the FSM shows a rotary switch that selects whether the compressor runs, etc. In fact, the heater A/C control head in this manual unit has transistor logic that gates power to the compressor and some other functions. The transistor gate for the compressor was shorted so the compressor ran all the time, except when the low pressure switch opened in cold weather.
Try the other possibilities suggested above but keep in mind that there are transistor gates to the compressor circuit (via the low pressure switch). Replacement transistors were cheap at Radio Shack (<$1).

racebum

mine gets weird like this from time to time also. it just dawned on me when i was reading this but what effect would unplugging the 2 pin weatherpack on top of the AC pump have? the part i hate is your fans always run when the AC is on.