Probably easy as cake, just wire a switch between ground on the frame and ground on the fan.
This way, you retain the factory ECU's ability to tr***** the fan.
Edit: UNLESS.... You got a relay tripping the fan, then you gotta ground the frame to the relay ground.
This way, you retain the factory ECU's ability to tr***** the fan.
Edit: UNLESS.... You got a relay tripping the fan, then you gotta ground the frame to the relay ground.