1991 Ford Mustang Unable to get the AC working in the car

BALL8565

MEMBER
1991 FORD MUSTANG
V8
2WD
MANUAL
105,000 MILES

I had the wiring harness changed to a painless wiring system. This system doesn't support the AC in my car. The mechanic cut the wires. I need to know how to rewire the system so that it will run without going through the computor? When I turn the switch to ac the blowers works and all of the vents move for the ac. I just need to know how to do the by pass from the switch to the ac unit.

1 Reply

AIRSOFTSOLDRECN9

MEMBER
348 POSTS

You mean wiring the compressor clutch correct? You need to run a 12V from the blower motor to the low pressure cutoff switch, then run the other side of the cutoff switch to the compressor clutch. Then run the negative/ground from the compressor either to your fan or a thermostat if you have one. If you run it back to the fan then when you turn the blower motor on the a/c is always running. If you run it through the thermostat then you will have temperature control and the a/c compressor will be variable. If you need a solenoid to kick up the idle speed of the car when the compressor is engaged then split your 12 feed to the compressor clutch to the positive terminal on the solenoid and then ground the solenoid to the engine or to the black ground wire from the clutch to the blower motor/thermostat.