1994 - New Compressor, Clutch Not Connecting

[vanhoogy]

I just got a new compressor and everything was working fine. Yesterday I started the car, the blower was fine but NO cold air. I checked the charge and it is fine. Heard that it might be the relay?

Anyone want to give it a shot and thanks!

[brcidd]

'94 H cars (as is yours) are known for relay contact issues-- tap on relay- usually 2nd from left on relay center on firewall- remove beautification panel to see relay center- if tapping on relay makes compressor come on- then replace it-- seen about 2 dozen H car relays act like this...

[Tech II]

How did you check the charge?

What is the low and high side pressures with the compressor not running?

On a cold engine, pressures should approx be the same as the ambient air, i.e., if the outside air is 70F, both pressures should be around 70PSI......if much less you have a leak......

If pressures are ok, remove the 2 wire harness from the pressure cycling switch on the accumulator......turn car and A/C on......now jumper the two wire harness......if the compressor starts, and low side pressure does not drop below 28-30 psi, need a new switch.....if it drops below that, you need more refrigerant.....

Also, if the compressor was short cycling due to low refrigerant, a code 66 may be set in the ECM, and it is disabling the compressor....

[imidazol97]

Originally Posted by vanhoogy

Heard that it might be the relay

You can switch relays in the center on the firewall. Most of them are single pole single throw like the compressor relay; the horn relay is in there and it's a good one to switch.

Just check the part number. Then if it works and the horn quits working, e.g., you know it's the relay.

[Bassasasin]

Hopefully you won't have to go this far but I had a blown fuse that feeds the power to the compressor clutch. I caused it. On my car it was located in a rare place deep above the right passengers foot. It's amazing that the PCM can somewhat detect these blown fuses with a professional code reader.