Fan override switch

[kgwmu]

Hi all,

Our car is an LS2 running off a modified OEM harness, we have a Ron Davis radiator with 2 14" brushed fans. The fans come on around 200 degrees, I'd like to add an override switch to turn the fans on as needed. I was told I should be using a double pull double throw switch to control putting power to the fans, based on what I've read it looks like I could just get away with adding a switch that grounds out the relay to complete the circuit.

How have you guys added a switch?

 

[Jersey_Jeff73]

i was thinking of doing the same thing but i was going to wire two new relays and switch with seperate fuses. i wanted to do it that way to be a complete separate circuit just in case something failed on the main circuit that runs off the computer. so if i lost a relay or a fuse i could still have it run also in my case i was going to add a water pump switch i have a electric water pump and would like to be able to run the cooling system with the engine off

 

[J Alper]

The Fans are Ground Control if it is a factory harness, 

Take a switch from ground on one side and run it to the ground to the fan relay to turn them on,  

 

[Rockwood]

i was thinking of doing the same thing but i was going to wire two new relays and switch with seperate fuses. i wanted to do it that way to be a complete separate circuit just in case something failed on the main circuit that runs off the computer. so if i lost a relay or a fuse i could still have it run also in my case i was going to add a water pump switch i have a electric water pump and would like to be able to run the cooling system with the engine off

A second relay in parallel, but controlled via switch would work. That, or as @J Alper says and just run a second ground to a switch. I always carry a spare relay anyway.