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View Full Version : Gen 3/4 Coyote with AC wiring Question



Sharris2
12-29-2025, 11:23 AM
As I’m in the planning stage wiring for my 65 coupe, Gen 4 coyote with A/C; id like to hear from others that have done this part of the wiring?

When I built my MK4 with a Gen 3 coyote, I wired it using the computer control to operate the cooling fan (no AC).

My question is do I NOT use the coyote computer to operate the fan and remove the fuse; use the Ron France wiring/temp switch and wire it as per the A/C controller?
Or is there a way to do both? I was thinking of wiring one-way diodes in the harness to protect everything?

Thanks

Scott

edwardb
12-29-2025, 03:10 PM
Had this question on my Coupe build (Gen 3 Coyote) and asked Factory Five. They said to wire both. Coyote wire to the fan plus the RF fan wire triggered by the thermo wire to the trinary switch. Either can start the fan. Or both for that matter. Zero issues after five seasons and almost 10K miles. Most of the time with the A/C running. The Truck build I did with an LS3 and Vintage Air system required the same approach and it too worked fine.