Engine fan with switch override

Hey guys. I am trying to wire my radiator fan to the ecu. But i would love to have a switch to override it just in case i need to cool the engine down after coming back into the pit. Currently, my radiator fans are hooked up to a switch to turn it on and off. Anyone can help me with me. I am on link G4 storm. Planning to use aux 3 for the engine fan

Hi Yuan,

Several ways to do it. Obviously you're using Aux 3 to switch a relay for the fans yes?

You can either have a override switch which will switch the relay on instead. Assuming you're setting up the Link to switch the relay to ground you can wire in a switch which goes to ground and also the same pin as the link. This will turn the relay on and the fan.

The other method, which I prefer as you can log fan state.

If using a G4 and not G4+

Wire the switch into a digital input (lets say DI1)

Setup Aux 3 as "GP Output", "Cond 1 or 2",

SW Cond 1, Aux Virtual value1 = on

Aux Virtual value1 = on, set to a spare virtual aux (lets say virtual aux 1)

SW Cond 2, D1 Value1 = on

DI Vaule1 = on, set to DI1 (Your fan override switch input)

Then go to your virtual aux output and set to engine fan.

This way the fan will either switch on based of engine fan settings or when it sees the switch input. You can then log Aux 3 status and see when the fan turns on and off either by the ecu or the override.

Okay. I will try it and if i do not understand anything, will come back again.

If i wire the switch wrongly to DI or aux3, will it burn the ecu? Thats what i am afraid about

It is possibly, although I would imagine only if you loaded the drive internally.

If you check out the help file it should show you how to wire a Aux output using a relay and also how to wire a DI