manual cooling fan toggle switch

[mug23]

Hello,

I'm looking to do a manual toggle switch for the cooling fan so I can control it. I'm looking or how-to and ideas on doing this.

This car is a track car that will NEVER be driven on the streets. All I need is to have the fan on when girding at idle. The main reason why I'm doing this is because my main wiring harness is hacked up and now the cooling fan wouldn't turn on by itself. Not 100% sure if it's the relay or what but I really dont want to spend too much time fixing this issue so I figure the easier way to fix this is to just install a manual switch so I can turn the fan on.

Anyone who is a wiring guru please if you can direct me the simplest way on how-to rewire up the switch or can us the stock relay but bypass the factory fan switch?

[Rasta Monsta]

Easiest way would be to use the factory thermo switch and a generic relay, and to create a separate small harness for the fans.

[mug23]

You mean I can buy a generic relay from like Autozone and just add a toggle switch?

[krystar]

yea. just bosch 30a. i thinke $7 at autozone

[Rasta Monsta]

Buy a generic relay and use the factory temp switch in the radiator to activate it. . .that way it will work automatically like it was intended (however it will run at full tilt with key off unless you use a key switched power source). Also, don't forget to use a fuse!

[mug23]

Should I use a 25amp fuse?

Thank you all for the info.

[djnolan]

it might be easier to repair than re-create. Try troubleshooting in this way...

1. With ignition on, touch sensor wire to ground. Fan should turn on.

If it does, the sensor is bad, replace.

If not check the fan motor next by jumpering directly to the battery.

If the fan works the problem is one of three items, the relay, the fuse or the wiring...

Check fuse first... duh

Checking relay is a little more dificult, maybe you have a known good spare to swap in... Hopefully this fixes it.

And lastly, if a known good relay doesn't fix it, start looking at your wiring for obvious signs of damage.

At this point you should know if the the fan, sensor, relay, fuse and wiring are good or not, and the culprit.

[WalkupManuel]

Easiest way would be to use the factory thermo switch and a generic relay

[zedsn]

The easiest way to run fans manually is take power from the battery then fuse it and then put the toggle under the dash and then wire it to the fans if you want a manual on off. That would not be using the thermo switch but would not take long to do at all.