[87chevy.com]

Originally Posted by Davidf

Yes, the factory ECU takes the 12v compressor clutch signal directly. So, you can simply tap off the Vintage Air compressor wire and send directly to the ECU "A/C Request" input.

Or, you can reroute the Vintage Air compressor wire FROM the compressor and straight into the ECU "A/C Request" input. But, then you have to use the a/c control (output) from the ECU to power a relay which sends 12v to the compressor. The ECU a/c output is a ground reference signal (used to ground the control input of the relay).

Simple. I believe ECU "A/C Request" input went away when a/c control function became part of the control/bus network...maybe 2002 or later.

Your "or" is what was implied, no monkey tapping into rigging mumbo jumbo... wire the vintage air signal to gm computer if its gen3 and wire it like a factory gen3. If its gen 4 or 5, similar just need the module to interpret and then send signal to GM ECU.. thats what i do for the genV ac signal request.
Vintage air signal to interface to stock gen5 ecu and works just fine. Why this big company is in the iceage on this is a joke.

Clint