No Air Conditioning

[rkball]

I've got a 96 SSEi pushing 293K miles. I noticed the air no longer works but worked great a couple weeks ago. I can bypass the AC Compressor relay and turn the compressor on. I tried a new relay and no luck. I think it may be that the A/C request signal is not making it to the PCM. I want to see if there is any voltage on the A/C lines from the HVAC Programmer to the PCM. From the probing I've done so far, it doesn't look like the PCM is allowing the A/C Compressor relay to activate and it gets it's request from the HVAC programer. I haven't ruled out the HVAC control module but everything else works except the A/C (no compressor on defrost either). My question is where is the HVAC Programmer located? I don't know which module it is behind the passenger I/P.

Thanks

[93RedSled-SSE]

My question is where is the HVAC Programmer located? I don't know which module it is behind the passenger I/P.

Thanks

It is the black plastic box that has all the colored vacuum lines going to it. On my 93, it is right of the heater box/air mix assembly and left of the PCM.

[drifter420]

The compressor will not engage if it senses too low of a pressure in the AC system. Try pumping some freon in ( and or check the pressure left in the AC line )

[rkball]

Thanks. I did think about the line pressure but I don't have the tools yet to check it out. This car has the pressure transducer feeding a signal to the computer. Not the limit pressure switches like earlier models. It's easy to check a switch but a bit harder to check a pressure transducer putting out an analog signal. I am not sure what level of signals should be present on the pressure transducer and what wire is what. There are three wires coming from this transducer. Anyone know what I should measure from this sensor, in the refrigerant line just off the compressor (right front of engine)?

[Bugsi]

Don't worry so much about measuring the output of your pressure transducer, worry more about actually measuring your AC system pressure. Just buy/borrow/ or rent a pressure gauge and stick it on the high side schrader valve. Turn on the system, jump your relay and measure it.