I have a temp switch in the heads and it will switch at about 185'. this will trigger a relay that turns on the fan. I want to set it up so that the fan will come on whenever the AC comes on as well. This will insure a good flow of air across the condenser if you are not moving.
Any one found an easy way to to do this?
Don

 

I use a relay on my electric fan also (Hayden p/n 3652). The temp switch just provides the relay with a ground to switch the juice on. Find a ground from the AC switch and pair it into the relay ground circuit - voila!

I patched in a dash switch to that same ground to turn on the fan whenever. Works great.

 

Check out the electronic fan controller made by Dakota Digital #PAC2000
http://www.dakotadigital.com/ I installed a dual fan assy on my darkside car(can't mention here) I hooked one fan to run with the engine temp senser. And the other fan runs with the A/C. The digital controller will allow both fans to run with the engine weather the A/c is on or off. I plan to purchase one myself soon, I talked witha guy at a car show that had one and he loved it.

Rod

 

As Randy Jack says, the temp switch provides ground to the relay, providing power to the fan. On my son's truck, I added a second relay, using the power from the A/C clutch to switch another ground leg to the first relay.

So the first relay gets ground from 2 places,
1 from the temp switch, 1 from the A/C clutch driven relay

Sam

 

Painless wiring should have a kit you are looking for as well.......just another option.

 

Thanks Sam.
I figured out how you did it with two relays. Found a couple of relays in the junk box and have it ready to install.
Don