I have a 2003 Chevy 1500 HD it has a duel climate control zones, turned the climate knobs to the lowest settings also the display has two settings recirculation and A\C buttons. I pushed the A\C button clutch comes on for a few seconds
and shuts off. Push the recirculation button A|C clutch comes on cools down pressures are good and temperature is coming out of vent 39 to 42 degrees. I removed relay in left side fuse panel under hood. I am getting voltage both A\C and recirculate switches. I did the jumper test on the and clutch clicks. I also checked A\C low psi switch getting 4.85 volts when either switch is pushed. I was looking in a Haynes manual, does the PCM ground the clutch relay for it to work? What type of scanner is used for OBD 2?
Looking at the schematic. The AC compressor clutch is grounded at the black wire and powered up with 12 volts at the DK green wire from the clutch relay. The relay is controlled by the PCM. The PCM activates the relay when it receives the ON input from the climate control module, and all other inputs are correct.
If what you're saying is correct, and AC works normally only with the re-circulation button applied, the problem must be in the control module itself.
But double check everything. Is the light on the AC button ON or OFF when the AC does not work?
Not sure what you mean by power from the AC and Re-circulation switch at the relay. The activation side of the relay always has power. The PCM completes the ground to turn it on.