I am just finishing an S4 NA swap into an 85gs. The wiring harness I got with the engine was missing the BAC connector. I have read a few threads as well as the FSM but I am still unsure about which wire goes where.

I currently have the B/W wire coming from the Main Relay and the L/G wire coming from the ECU. I have a picture of the BAC and I just need to know where the B/W wire goes. Does it go with the red terminal or the blue terminal? I don't want to hook it up wrong and fry the BAC. Any help would be much appreciated!

Thanks!

 

It's not polarized. It's just a solenoid coil inside, like a relay. Your B/W wire is the +12V and the L/G wire is the pulsed ground wire from the ECU.

 

Didn't know that, but now I do. Thank you.

 

yeah if you take a BAC valve off the car you can put power and ground to it on either pin.

 

thanks for the help!