Bought a car with a full wire tuck and the fan was never installed, there were a blue and a black wire with a connector out near the core support, and the blue has power when the key is on, I checked all the fuses, and located what I think is the fan relay, (4 POLE, 2 HOT 2 GROUND?) in the passenger fender well, I tried jumping the sender in the thermo housing and no luck. the car has a B18c and a OBD0 -OBD1 rywire harness, and it also looks like he cut all the a/c **** out of the harness
the fan works I checked it before I put it in.
should the fan be hot with the key on and the relay send it ground to turn on?

or is this a can of worms I don't want to open and just install a switch?

 

anyone?

 

it should not be always hot.. the thermo switch should control the fan going hot, and the ground is always hooked up, not the other way around.