Okay, I took the intake manifold off to check for a vacuum leak (I think I found it), and found a one pin, Green/Black wire connector hanging loose on top of the engine. It comes out of the harness near the primary fuel injectors (sitting right behind the alternator) and near where what appears to be a sensor in the water pump. But it wasn't connected to anything and I don't know where it goes... if you have a clue, please let me know ASAP!! I'd like to put the manifold back on tonight!!!! Thanks a bunch!

Its an N/A, Series 5 engine.

I'll try to add a picture here soon but please answer before then if you can!

Thanks!!!

 

Sounds like the thermo sensor wire for the auxiliary fan.

 

Here's a picture:

 

Where does it connect to? I don't see a wire or plug anywhere near there.

 

I don't have a 89 and newer manual.......but if one looks at the 88 online manual and the schematics, you will see on page 50-38, that there is a green/black wire that goes to a water temp switch. This water temp switch is peculiar to cars that came with a electric cooling fan. Cars without the electric cooling fan might/probably have the electrical plugs just laying around not in use. Its easier to make a harness for all applications than a dozen for different configurations Get my drift?

Cars that have an electric cooling fan, have a water temp sensor located in the base of the water filler housing. Usually there is just a blank boss on it where the sensor would have gone.

Those cars had the regular belt driven fan, but also a small cooling fan in front of the A/C unit in front. Forget about the plug if you have no electric fan.

 

Awesome... thanks a bunch. I was worried for a bit. I have the e-fan, but there is absolutely no place on the water thingy for a plug, so I just left it as it was and merrily went on my way.

I set a new personal record for removing the intake (up to the point shown in the pic)... 45 minutes to get everything off, cleanly and neatly. Another ~45 to get it all back on. I didn't depressurize the fuel system, I just tied the injectors to the rail with some wire and sorta gently moved the whole assembly around. It was a pain, but not half as bad as depressurizing the fuel system, repressurizing it, and (in my case, for whatever reason) unflooding the engine.

 

On S5's the electric fan's thermoswitch is mounted on the back of the water pump next to the ECU's thermosensor.