My radiator fans runs at high speed but usually when I start my car in the morning the relief relay( the one in the dash next to the steering wheel) will chatter with the radiator fans coming on and off in time with the relay chatter.

I usually pull the cooling fan fuse in the drivers side kick panel to get it to stop. Ive checked out the forum and some people say the engine coolant temp sensor is bad but my temp gauge works as the temp rises when I have the fuse out, so I dont know if that is the problem here and I dont think its the relay itself as most of my accessories work. Right now the Cruise, AC ,and the gear selector display are kaput so are those controlled by the relief relay? The fans do come on with the AC though.

My mechanic said my thermostat is stuck open so could that trick my car into thinking its too hot?

Also I guess the retarded guy I bought the car from put radiator fans from a 1990 '90 in there as he couldnt find propper replacement in any junkyard, so does anyone know if those fan motors run on a different amount of power and that is what is causing my relay to mess up?

Any insight or ideas are greatly appreciated. oh yeah this is in a 1992 100s no-quatrro.
Thanks,
Tyler

Try unplugging the wires from the switch and see if the fan dies.

That switch triggers the high speed relay.

What I've found is because the fans have been running on high speed for long periods of time the relay gets overheated and becomes erratic or even welds itself closed. It's not designed to run the fans for long periods of time.

In your case since the previous owner already replaced the fans I would say that the radiator thermoswitch has been bad for a long time.

I'm replacing my radiator thermoswitch plus the high and low speed fan relays on my car today for that very reason.

The parts are cheap compared to a cylinder head gasket replacement.

I cut open the old thermoswitch from the radiator. The electrical part was in perfect condition - no arcing or burning of the contacts.

The problem was the "plunger" that activates the contacts had jammed. This plunger slides inside a tube and it had step worn into the side of it.
The step prevented the plunger from receding away from the switch lever.