[GMC72BB]

I just finished installing a VA in my 72, couple things, I did use the brown original wire for switched positive circuit, there is a red wire from the VA that goes to the battery, with a circuit breaker inline. You could hook to the switched circuit on a aftermarket wiring block. Don’t confuse the violet color wire in the VA circuit , to the violet wire from the harness, the violet wire in the new VA is for a wide open throttle switch. as that is not used , chances are. if you use the original controller. The original switch controller conversion isn’t hard , just be sure to follow the directions on setting the levers. You have to program it, once done. That is done via a supplied jumper wire. Again not hard just read instructions twice ( for me anyway) before you do the programming . It doesnt use the original fan switch, but it is still there so looks original. This is the second one I have installed ( last one in 69 camaro) with this one, the minute I hooked up the wires, it turned on, never had that happen, but once the jumper program wire was hooked up, it stopped the fan running. It says some time you have to repeat the programming process. Mine programmed the first time. I haven’t charged the system yet, but I did the last one myself, will this time too.these new VA systems on the wiring is basically plug/ play, the relay, circuit breaker etc is already wired, just run the wires and plug into the system, have to hook up 2 grounds( white wires) Be glad to answer any other question if I can.