ok here are the hints:
1. it is black
2. the shape is round
3. one hole where pin goes in
4. green wrie w/ black stripe & black surround
5. it is at the end of the harness in the group of wires with the pirmaries and water pump plug

I put the whole thing together and it ran like *** so i took the manifolds apart to replace the rubber fuel injector grommets. I had this sticking out near the alt. but could not find where to plug it in. I don't know if this plug has anything to do with the poor running or not.
Ask if more pics or info could help.....

 

that looks like the plug for the fuel adjustent. the dial located ight next to the MAP sensor.. although what the hell is it doing near the alternator?? but i could be wrong. but ive only pulled harnesses from s4's sorry

 

oh sorry i forgot to mention that this is a s5 N/A what is the MAP? oh and BTW the plug could go many ways, i just chose to stick it out that way, it could go out the back of the engine as well

 

who shall win the grand prize? is it a plug for the MAP sensor (i still don't know what or where that is) as alwayssideways said? or could it be an optional plug for the water pump?
If sommone could fill me in on this map thing that would be nice

 

You know I have the same problem. That connector wasn't connected to anything before I broke my engine down for a rebuild. I still don't know were it goes. Ican't find any place for it.

 

Ignore all of the above...

Correct answer: temp switch for the auxilary electric fan fitted to some models. If you don't have the fan (located in front of the AC condensor) then you won't have the temp switch, hence the spare plug. If you do have the fan, it should be plugged into the back of the temp switch on the back of the water pump housing.

 

Thx!

 

I think we have a winner!!! someone else illuded to the same thing in another thread, so mine does nothing, ok then.

 

oh yeah!!! that would be it!!! the s5 t2 motor i got had a conector that would fit something like that!!! totally forgot about that