Originally Posted by
Josh
So I am just finishing up my wiring harness and I am second guessing my fan relay wiring. I have opted to do a MS controlled circuit dependent on coolant temp and eliminating the otterstat. However, I also want the fans to engage when the A/C clutch is engaged. So this confuses me. I know you can switch a relay using IAC1A and IAC1B (same goes with the IAC2 ports) and they are inverse to one another (one 12V one ground). But the A/C clutch outputs 12V so to prevent going to a double thrown relay I was wondering if I could just use a chassis ground and power the relay with just IAC1A (configured accordingly as a 12V output), or since IAC1B is not used no current can be output? I have attached a schematic for clarity, just wondering if the proposed idea will work. FYI I am using a 2 wire IAC so i am controlling it with the FIDLE circuit.