Ill post some pics later, but it just came to me that i have been wanting to know what this is. At the end of my s4 TII engine harness there is a plug with a relay looking thing on it. I have been up and down all the FSM and Wiring diagrams and have found no answer to this. It doesnt seem to do anything because i can unplug it and the car runs the same. I would just like to know what the heck it is.

 

Location? "End of harness" makes me think of the primary injectors, or the CAS/alternator end...

 

yea its at the end of the engine harness it ends up over by were the MAF is and the fuel pump relay, the plug on it is pretty large compared to the other ones. Like i said none of the FSM wiring diagrams have anything about it.

 

S4, anyway, all you have over there from that particular harness run is the AFM connector, TPS test connector, check connector, and idle mixture adjust potentiometer (it's got a fairly large round plug-is that what you're talking about?)

Only other "relay looking thingy" in that area would be the air bypass relay mounted in front of the airbox area, I think it's on a different harness though...