Where to connect trigger on new HX?

I’m gearing up to install a used C&R Revan heat exchanger I picked up and found some conflicting information about where to hook up the trigger wires from the relays. The instructions on his site say to attach to key on power in the fuse box. Doesn’t this mean fans are going all the time, even when the pump isn’t?



But there also is a wiring diagram on his website that shows to connect the trigger to the white power wire on the pump. There is also an old VMP video where they install an AFC0 to the white power wire on the pump.



Is there be any teason to having the fans trigger with Key on when the pump isn’t activated?

Car details:
Weekend toy
Occasional short WOT or rolls
Currently running aftermarket intake, tune, 170 t-stat
Stock Eaton, stock pulley
2.5 pulley is on deck for next mod after HX is done.

Logically, the fans should be on only when the fluid is circulating, but you can wire them up virtually any way you see fit for your car. I have mine turn on with the IC pump. I can give you specifics if you need.

I also have a rear ice cell. When I turn this system on, it runs through its own dedicated lines, with the only common component being the intercooler (H.E. in the lower intake). When I switch this system on, I wired it so that the front pump and fans turn off. (No flow, no need fans.)

I found the same issue when I installed mine. It’s currently wired to key on.

But it sounds cool with those giant fans running right before I fire it lol

Zedeater said:

I’m gearing up to install a used C&R Revan heat exchanger I picked up and found some conflicting information about where to hook up the trigger wires from the relays. The instructions on his site say to attach to key on power in the fuse box. Doesn’t this mean fans are going all the time, even when the pump isn’t?

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Answer is no. Key on power only goes to the fan relays. The fan relay coils are only energized when the pump is on, closing the normally open contacts of the fan relays, which then power the fans.

Depending on your tune, the pump may not be on at all times. You may also want the ability to run the system with the car not started or while your driving. You'll need a switch that starts the pump to do that. I chose to wire a switch into the actual pump relay wiring. Had to find the pump relay which is in the small panel box on the p/s shock tower. Using the diagram on the relay, I found the two wires underneath for the normally open contacts. Spliced my override switch wiring there and routed into the cabin. This switch has no effect or interference with normal, tune, or temp operation of the pump.

Use the pictorial diagram you posted for the wiring.

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Willie said:

Logically, the fans should be on only when the fluid is circulating, but you can wire them up virtually any way you see fit for your car. I have mine turn on with the IC pump. I can give you specifics if you need.

Click to expand...

I appreciate the offer, we ended up going to the white wire for the pump.

03 DSG Snake said:

I found the same issue when I installed mine. It’s currently wired to key on.

But it sounds cool with those giant fans running right before I fire it lol

Click to expand...

LOL, no doubt like it’s preparing for take off!

ZOMBEAST said:

Answer is no....
Use the pictorial diagram you posted for the wiring.

Click to expand...

Done as suggested, thank you.