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View Full Version : RF Harness & FFR Thermostatic Switch



DrMiller
08-12-2016, 05:53 PM
Greetings, All:

I searched for an answer to my dilemma, but the threads I found all contained information on how to bypass the situation by purchasing other thermostatic switches, or other workarounds. I'm trying to find out exactly how to run my cooling fan with the Ron Francis harness and the thermostatic switch provided by Factory Five.

Having just fired the motor for the first time on Wednesday, I proceeded to hook up the complete kit provided fan, and attached the green "fan thermo switch" wire in the sender portion of the harness to the FFR supplied thermostatic switch. This immediately starts the fan, which threw me until I looked at the relay and realized it has constant power coming to it and the fan thermo switch is providing ground.

My Questions:

Is the thermostatic switch from FFR supposed to be normally closed or open when the motor is cold? (Mine is closed so I want to make sure it's not an issue of a bad switch.)
Assuming it is normally closed, what modifications do I need to make to the RF harness or relay to make this function correctly?

I know there are other options, such as purchasing a painless wiring switch, or a manual switch on the dash, but at the moment I'm specifically interested in making the FFR switch work with my RF harness.

Thanks in advance for any assistance anyone can provide...it is greatly appreciated!

rich grsc
08-12-2016, 06:47 PM
Normally open, closes at temperature to switch on the fan.

GoDadGo
08-12-2016, 06:57 PM
Ground it out and the fan should come on.
Also, you may want to install an override switch.

DrMiller
08-12-2016, 09:09 PM
Normally open, closes at temperature to switch on the fan.

In that case it's a bad switch - it is closed sitting in the manifold on a completely cold motor.

DrMiller
08-12-2016, 09:12 PM
Ground it out and the fan should come on.
Also, you may want to install an override switch.

That's the problem at the moment - the minute you attach the green wire to the FFR switch the fan comes on and will not shut off, even with the motor stone cold. So I'm starting to think I have a switch that is stuck closed providing ground when it should be open until it gets warm based on Rich's comment above.

GoDadGo
08-12-2016, 09:31 PM
Bingo! The switch is bad.

DrMiller
08-12-2016, 10:49 PM
Many thanks to rich grsc and GoDadGo!

j.miller
08-13-2016, 08:59 AM
I KNOW THIS ONE !!! it's the switch!........late again, story of my life ! DANG !!!

rich grsc
08-13-2016, 09:07 AM
I KNOW THIS ONE !!! it's the switch!........late again, story of my life ! DANG !!!
Thats OK, everyone who plays gets a star. :rolleyes: