Geoff1200

Not sure if this is the proper place but....Transplanted a crate LS3 into a 67 chevelle. The ECM has a wire labled "FAN", do I still need a pair of relays for the Spal dual fans? Will both fans run when ECM trigers them? How about the A/C switch for the fans? Am I making a mountain out of a mole hill? Appreciate any guidance

Compsystems

is this an E-rod kit or something else you got the motor from?

If its an E-rod follow the manual for wiring the fans.

If this is just the PCM wire then it is a ground trigger for the fan relays.

Geoff1200

it's a GMPP crate system from Pace. Destructions state to wire fan directly to the blue wire labeled fan. Don't know if both fans run at a constant speed or is there a hi/lo function? Still have no clue what cycles a/c compressor. This is a ground-up resto-mod that's nearing completion...I think

mikes50

I have a GMPP LS3 crate also, wired blue wire directly to fan, relay is built into Fuse/Relay center.
I don't see why it wouldn't power both fans. It is set to turn fans on at 207* F.
Not sure on Hi/Low.
It is a 12 volt signal

Geoff1200

Thanks Mike, what did you do about the A/C compressor?

mikes50

Not running A/C.

jimmyblue

iTrader: (11)

My opinion is that fans are better off run thermostatically
based on radiator outlet temperature, than letting the
PCM guess and meddle. Better to have the radiator
water 20 degrees below block, to have some "surge
cooling capacity", than make thermostat sit there full
open waiting for fans to decide to play catch-up.

Unless your primary goal is to shed load for CAFE
compliance. Which is nobody's other than the OEM.