What sensor is it (LT1)?
 

Anybody able to tell me what this wire is? It's on the passenger side right between the back two cylinders. It's a green plug with one wire (that I believe was brown or purple).

It's in my 1994 A4 Z28. My 95 M6 and brother's 97 M6 don't have it.

http://img6.imageshack.us/img6/5139/1126111615.jpg

Coolant sensor that should be on the driver side.

For the gauge too. Might be a used head or something like that.

I have a coolant sensor on the other side though.... I can understand if it's a used head but why is it plugged in lol?

Might just be some lead on it unless you have or someone had an aftermarket gauge?

No aftermarket gauge in the car, maybe at one point it had one though.

I didn't bother tracing the wire either. I saw it and was like "what the hell is that" and my buddy looked at it and was clueless as well.

could be coolant fan switch

They are controlled by the computer via the 2 wire coolant temp sensor in the water pump.

From the factory that port isn't used on F-bodies.

Not sure it the vettes or impala SS may have used the sensor on the passenger side?


Another option is that Hypertech sold a kit to bring the fans on early (185 degrees) You used a sensor in the passenger side head and it tied into the connects by the ECM, basically overriding the sensor in the water pump for the low speed fan, so 1 wire into the connector is used. Trace the wire, it probaly goes to the 12 pin connector near the ECM if that is a low temp fan switch.

Back in the early LT1 days these switches + thermostat swap was a cheap and easy mod that cost allot less then getting the ECM reprogrammed. I actually still use mine.

Never knew about that, pretty neat.