My fan switch seems to have a mind of it's own. I can turn it on and off once or twice; but after a second attempt at the cycle, it will turn on but will not cut off thru the switch. I can kill the ignition to stop the fans. The wire is not severed in any place; it is hooked to the switch securely; where it passes thru the firewall, it is wrapped in a thick roll of electrical tape; the ground is screwed tightly into the underside of the dash (metal part, of course). So then, what am I missing here?

Thanks,
Eric

 

May be grounded to metal, but it that piece of metal clean and grounded itself? Check it with a light to be sure.

Also, are you running the power through a relay? May be too much amperage through the switch if not.

 

No relay, the wire running into the switch is crimped directly into the connector (at the sensor) that has the wire coming from the fan/harness itself.

The ground is actually the metal part that the plastic panel (fuse cover area) under the steering column screws into. If that isn't a good place to ground, can you or anyone suggest a better place? Along those lines, can someone explain why it will work a couple times and then refuse to turn off?

 

I agree the most likely cause is too much current going through the switch contacts, overheating and making them sticky. I'd be inclined to fit a suitable relay to do the switching of the fan and just use the switch to flip the relay.

 

Thanks for the replies. The solution was the ground. It was hooked under the dash; I removed the kick panel, drilled a hole, and installed it there. Problem solved. My switch can handle 20 amps/120-some-odd volts so I don't think the switch was lying down on me.

Thanks again, hope this will help somebody else with this mod.
Eric