DavidF, I thought of something today might be helpful to pass along.
I mentioned in an earlier post that a local hot rod shop advised me to activate the condenser fans with a relay that was energized from the condenser (in my case, off the binary switch).
I had planned to wire the condenser fans with a fused line directly off the binary switch. I figured that since the AC system had its own feed that went hot through a relay on an ignition-switched line, I'd be good since the fans would only run when the compressor was on.
The technician at the shop told me that the electric condenser fans would spin on their own with normal driving because of the wind going through the blades. It wouldn't matter if the fans were turned on or not...they would spin when driving. He explained that the little DC motors in the fans would act as tiny generators and produce a small amount of current when spinning in the off mode. This current would work its way back through the circuit and would make its way to the compressor through the binary switch because the flow would be unchecked in this direction. He said this would cause premature failure of the compressor. Solution? Same concept, but use the binary switch wire to trigger a relay for the fans and give the fans a separate power source instead of wiring them directly to the compressor hot feed. This would eliminate backflow of current if the little motors did become generators. The backflow stops at the relay.
Made sense to me, so I did it this way. I wouldn't have thought of it had I not received the tip, so I thought that I would pass it along. Could be how you planned to do it anyway.
Maybellene
