964 A/C Question

[Adidas]

1993 964. Not getting 12 volts to the a/c compressor.

The button on the climate control unit engages and the light comes on.

The A/C compressor fuse in the engine bay is good. The front condenser fan fuse is good as well

Not sure if the front a/c blower relay is good or not.

Any method for testing the relay or a compressor wiring diagram to check for wiring issues. Would a low pressure switch interrupt the circuit to the compressor if the system is too low on freon?

[964TargaC2]

if system is too low on freon compressor wont engage

also check the connector, it gets corroded

[walt]

The compressor clutch will engage at far less than 12V. My Sanden 507 pulls in at 8.2 V., I've been told it will engage at 5V.

[budge96]

Originally Posted by Adidas

1993 964. Not getting 12 volts to the a/c compressor.

The button on the climate control unit engages and the light comes on.

The A/C compressor fuse in the engine bay is good. The front condenser fan fuse is good as well

Not sure if the front a/c blower relay is good or not.

Any method for testing the relay or a compressor wiring diagram to check for wiring issues. Would a low pressure switch interrupt the circuit to the compressor if the system is too low on freon?

System low on freon will disable the compressor circuit , once recharged the compressor clutch will engage ..
Bert

[Paperboy]

The A/C compressor has a relay in the rear fuse box lhs of the engine bay.
A. Test/check the relay.
B. If the relay is OK , if you quickly jump the relay the A/C clutch should engage and turn the compressor. If this works it could be as mentioned above the freon level has dropped below a cut off level, and you dont get a signal to the relay.
I made a small jump connector with an on/off switch w 30 amps fuse capacity.
( I think it is terminal 30 and 87 you jump, but check this. Was a while since I did it.)
I assume the condenser fan does not get a trigger signal if there isnt one to the compressor. You can jump this relay in the front fuse box as well to check .( I think it is 30c and 87 c for low fan speed, 30 and 87 for high speed)

[JSny]

Advice if you need a recharge: add some fluorescent UV dye to the system. The next time the system leaks you can easily find it with a black light. The dye is cheap and is less than an once.