Quote:
Originally Posted by Hart_Rod
Thanks for the info. Does your compressor come on and stay on until you turn it off? Mine isn't it's cycling on and off and I assume it is being controlled by the computer, which would lead me to believe that it has some over/under pressure protection that is being provided by the PCM. But I would like to be certain because I don't want to damage anything. Thanks again. FYI, I'm using a 2006 Tahoe P59 PCM. More info here: http://67-72chevytrucks.com/vboard/s...=709611&page=2 |
Yeah, mine will cycle due to to the low pressure switch being in series with the signal to the A/C clutch relay. When the pressure gets too low, it goes open to cut off the compressor, and prevent the evaporator from freezing up.
To confirm how yours is controlled, you'd need to trace the wiring. If the trigger wire to the relay is coming from the PCM, the PCM is controlling the cycling. For a 2006 PCM to do so, I believe it would need to have a serial A/C request in most cases. I have heard of a few cases where people were able to get the later PCM to accept a 12v+ A/C request, but in talking to a few tuners and harness builders, it was hit or miss on success.
If the trigger wire is coming from the low pressure switch on the accumulator (assuming you have one, and aren't using a POA valve system), the cycling will likely be controlled by that switch.