Temp sensor itself plugs into a small hole from behind the air dam/spoiler, driver's side under the headlights. It's a second hole underneath a mounting screw hole. Reach in under front bumper and above the spoiler and you get access the wiring. (Parking lights wiring is there too.) Sensor itself has about 12" wire and is plugged into wiring to the car. That's the way it is on my 87 325iC.