it is in one of the plugs that go into the factory ECU, when you see the plug its really obvious which wires you jump.

 

teh a/c wires are in the part of the harness that runs across to the driver, not the harness that goes into the engine bay. The wiper harness is part of teh harness that goes into the engine bay, but is easily separated without cutting any wires i believe

 

Im not saying the ac wires go into the engine bay with the engine harness, what im saying is the ac runs THROUGH the factory ECU.

This whole topic is only relevant to someone who has removed thier factory ECU.

And yes the wiper harness can be seperated from the rest without cutting wires, just have to take the harness apart a little bit

 

Here is the harness you need to jumper to get AC control to work from the dash button. Like Rob said, it's the BLUE/WHITE wire and BLUE/ORANGE wire. They are 3 slots over from the end, and are right on top of each other.




I also soldered and electrical taped my connections. Now you can have a standalone with AC.
Go to my blog for larger pics.

 

sorry to bump an old thread, im trying to do this rn with my S5 FC and the blue/white blue/orange are in different pin locations. im assuming yours is an S4?

also, with the 2 wires jumped at the ecu, will i need to do anything else? my ac system is currently empty and wont kick on. is there a way to bypass the pressure switch so i can test it out for a second before i commit to charging the system?

TIA