Fan Connection on an Edlebrock Pro Flo 4

Both the FF instructions and the Pro Flo 4 instructions indicate it's better to control the cooling fan with the EFI computer rather than the sending unit(s). For those of you who've installed the Pro Flo, correct me if I'm wrong. The only thing I really need to do is tie the brown/yellow "Fan #1" lead on the Pro Flo harness into the dark green sending unit wire on the FF wire harness. Effectively bypassing the temp sensors on the engine or radiator. Does this sound right? The FF fuse block already has a 30amp fuse and Bosch style relay, and is already connected to the battery, ignition, and fan.

I bypassed the RF fuse panel and relay for the fan entirely, and added a relay for the fan to an array of relays on my firewall for things like fan, fuel pump, etc. I did use the RF wire that powers the fan, and extended that to the relay on my firewall, and the relay is triggered by the Fan#1 lead on the ProFlo4 harness. So, the temp sensor in the Edelbrock manifold that came with the ProFlo4 is feeding info to the ProFlo4 computer to turn the fan off and on. I have mine set at 195 degrees, five degrees higher than my thermostat. My build thread has pics of this stuff, if it's helpful.

Greg

Thanks. I think what I posted above should work. The only thing that gives me pause is that the Edelbrock wiring diagram has the ignition and temp sender wires reversed on the relay compared to the way FF has it wired. I'm just trying to minimize adding wires and relays if I don't have to.

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Originally Posted by Robk

Both the FF instructions and the Pro Flo 4 instructions indicate it's better to control the cooling fan with the EFI computer rather than the sending unit(s). For those of you who've installed the Pro Flo, correct me if I'm wrong. The only thing I really need to do is tie the brown/yellow "Fan #1" lead on the Pro Flo harness into the dark green sending unit wire on the FF wire harness. Effectively bypassing the temp sensors on the engine or radiator. Does this sound right? The FF fuse block already has a 30amp fuse and Bosch style relay, and is already connected to the battery, ignition, and fan.

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You're correct if the fan wire from the ProFlow is a ground wire. All you need to control the fan using the RF harness is a ground connection on either of the RF harness fan thermo (green) wires. The relay controlling the fan has power and just needs a ground to complete the circuit. The EFI computer is simply connecting the fan control wire to ground internally when the coolant hits the desired temp.

It is indeed a ground according to the Edelbrock manual. Should work fine. I just don't understand why the ignition and sender wires are reversed compared to how FF wires the relay. My novice best guess is you have to have power to one side and ground to the other to complete the circuit and for the relay to actuate. Technically it doesn't matter which side is which.