My car didnt have one when I bought it. It has one yellow wire comining out of the wiring harness on the passenger side which I was told was the wire to the air temp sensor that went into the stock air box. My car has a K&N filter on it so I have no air box. I need to know if the yellow wire is the right wire for that sensor, and if there is another wire to ground the sensor or if I need to ground it myself. Thanks.

 

Air intake temp sensor is a part of the AFM on a series four car.

 

Hmmm....is there any other sensor that would use a thick yellow wire that has voltage to it?? Its on the wire harness that comes off of the AFM side and heads towards the firewall on the passenger side?