Like the interior air temperature sensor, the exterior is a thermistor with a temperature dependant variable resistance. But unlike the interior air temperature sensor, no additional parts are required to prevent stangnant air from causing false readings as the sensor is in the air flow path of the radiator and condensor.

The exterior temperature sensor mounts on the plastic conduit where the 14290 headlamp and abs harness crosses in front of the a/c condensor. My police interceptor already had the cutout in the plastic, so the sensor just snapped into place.