I'm looking to set up a manual toggle switch to operate my radiator fan. It hasnt worked for about 2 years and I've already gone through everything I could think of to fix it. (relay, temp sensor, wire condition, fan itself) I've decided it's just simpler and more reliable for autocross to wire up a toggle switch to operate the fan. (battery to switch, switch to relay, battery to relay, relay to ground, relay to fan, fan to ground + in line fuses in the system) What amp relay is recommended to operate the fan? (low speed) Am I forgetting anything?

Thanks for any input!
-Luke

 

Just use the one that's already there. It's free. I guess it's actually ground switched, but you can check me on that.

They use a lot of electricity. It takes a big relay to pull one.

 

At the radiator fan RELAY, there are two small ground wires. You ground one of them to turn on the fan, one is low speed, and one is high speed.