Dual Fans - Vintage Air - ProFlo-4 ECU

[C10forDad]

I have seen lots of posts out there about LS swaps and VA trinary switch wiring, but surprisingly none with the ProFlo-4 setup.

I am attaching a PDF of a wiring diagram that I believe is correct.

I am looking for some validation and if it isn't right, some clarification of what should be done.

This is what I believe to be correct so far...

1. ProFlow-4 ECU has the following
   • 2 Ground activated output triggers from its ECU that get wired to their specific Fan Relay
   • 1 Key on 12V+ that gets connected to both of the Fan Relays
2. The Trinary Switch has the following
   • 1 Wire connected to the Compressor
   • 1 Wire connected to the Vintage Air Compressor Relay
   • 1 Ground
   • 1 Wire that gets connected to only the Fan #2 Relay

I did find that the ProFo-4 ground activated output triggers from its ECU can be programmed to activate at different temperatures. This makes sense since there are two separate wires.

The logic that I was trying to wrap my head around is that the Trinary Switch is asking for both fans, but really only needs to request the #2 fan. This logic is sound for these reasons...

• Both fans do not need to be on if the engine is cold while the AC is on
• If the engine is at operating temperature, the AC is on, and the head pressure is not high, then Fan #1 will already be on.