I have a 2001 Yukon XL with the Red and Blue connector PCM and added electric cooling fans controlled by the PCM. I inserted a wire in terminal 42 of connector C1 (Blue) for the control of one of the two fans with A/C off. That will handle one relay. My research with a 2001 Corvette (same PCM) connector C2 uses terminal 33 for the other relays. My PCM uses that terminal for TCC Brake Switch Signal. The PCM has the ability to control two fans according to the OS. Does anyone know which terminal it uses to control the second set of relays? I have to believe if the OS has the ability to control two fans then there should be a terminal that controls all the relays. I did this to get away from the clutch fan that is so noisy and to shut off the fans at highway speeds as they are not needed. The fans are currently installed and cooling just fine as I used the A/C clutch apply signal to trigger the other relays. The only issue is when the a/c turns on only one fan operates the other one turns off and as long as the A/C compressor is on the fan stays on even at highway speeds. Has anyone added electric fans and knows which terminals control the relays? Thanks