what is this?

Sorry no pic... so I'll try to be as descriptive as possible. I'm trying to figure out which sensor/connection is the one just to the left of the oil filter looking at the engine from underneath the car beneath the intake manifold. I'm asking because yesterday while changing my oil I saw where it finally was supposed to go after owning my car for over 2 years. This particular connector has been by-passed with a paper clip jumper (in the female part... male connector comes out of block) forever. Hell, the redneck mechanic who replaced my engine didn't even connect it. The reason I'm finally asking about it is because I never thought it was that important. Anyway, after plugging it in and resetting the ECU... finally no more blinking... no more codes... yippeee!!! Car seems to operate smoother now too. If anybody knows which connection this is please let me know. Thanks.

BTW... it's a two wire connector with two prongs

that is the fan switch. It tells the fan when to come on. By jumpering it together, the fan will come on with the ignition.

black rubber "boot" cover, yellow and black wires, small off-white banana plugs.

I had my fan hooked up to the ignition when I replaced the engine so it comes on all the time. Does this matter? The fan still comes on all the time.

If you plug those two wires into that switch, the fan will not come on with the ignition. If you jumper the two wires together with a paperclip, it will come on with the ignition.

It doesnt necessarily hurt anything except for draw excess voltage from your alternator/battery and make the car not warm up as quick.

maybe I plugged it in backwards :dunno: but my fan is wired up directly to the ignition module (fused) above the fuse box underneath the dash. I'm not throwing codes so that's a good thing. I just checked it and the fan still runs all the time. Actually seems like there is more electrical power now. My brakes used to feel mushy under load but don't anymore. I reckon I'll leave it as is. Thanks for the clarification.