mrnastix

Recently i purchased a new-to-me 91 5.0.. It has an electric fan conversion with a relay from the previous owner, it was working fine up until the fans stopped kicking on and it would overheat. I found something online about grounding out the wire coming off the fan switch, so I grounded it, and the fans came on. First thoughts were I had a bad fan switch so I went ahead and ordered a new fan switch off summit(Vintage Air 11190-VUS electric fan temp switch) that turns the fans on at 192F and a Mishimoto 82C thermostat. I install everything and I am having the same problem, I dig through the net some more and find that some people people have their fan switches installed on the thermostat neck as opposed to the lower intake manifold how mine is. I go ahead and switch the location of the switch and the fan comes on as its supposed to at the correct temperature; except now it won't turn off(and brings the temperature of the motor really low) unless i disconnect the wire going to the switch.

Sorry for the long paragraph but i did my best to try and explain the problem.

Hopefully someone can point me in the right direction for test/solutions to this problem. Thanks in advance!

mattdel

Seems more of a coincidence than anything else, to me. I'd say you have a sticky relay.

mrnastix

I don't think the relay is sticking otherwise the fans wouldn't shut off when I disconnect the fan switch wire

Bubba 95SN

Why not just test the relay?

mrnastix

just went ahead and tested relay and it's fine. i put power to the coil side of it and it clicks on and off fine.

Tony71502

Go put a mechanical fan back on. They are cheap if not free... and you won't have to worry about this junk anymore.

E-fan only frees up like 3-5 horsepower of parasitic loss.

mattdel

One thing I just thought of: If your temperature sensor is deep enough to touch metal on the inside of it's port, it could ground the sensor out, which could cause the symptoms you have. It's not meant to touch anything but coolant.