It's a bit of a mystery, but I consulted with my very smart psychic wife, and she opined that you probably have an '88 Corvette.
And she thought that you're probably asking about activating your radiator fan with a switch. Your question doesn't give us much of a clue, but since she's usually correct, I go with that.
She suggested that you fill in your personal information, so I wouldn't have to bug her so often!
I'm not sure when they converted to the computer controlled fan, but If the '88 is like my '84, here's my technique:
The wiring from the Coolant Temp Switch (CTS) in the head goes to the fan relay, which is located on the LH inner fender panel, below the brake master cylinder. On your '88, I'm not sure whether the CTS is in the LH or the RH head. In my '84, it's in the RH head, between cyl 6 & 8. I think yours might be between 1 & 3.
The wiring goes thru the firewall connector as a loop between the engine harness and the body harness, so the wiring is already thru the firewall! This connector is to the left of where the steering column goes thru the firewall. A switch between that loop and ground will activate the relay! An even more useful feature is an LED on that wire to indicate when the fan is activated!
(large image modified to link-aapple)
|UPDATED|2/24/2018 7:45:27 AM (AZT)|/UPDATED|
______________