The ambient air temperature sensor is a variable resistor interfaced to the Body Control Module (BCM). The BCM provides the logic for reading the ambient air temperature. The ambient light sensor is on the dash. It works with automatic lighting functions, will read the outdoor light, and sense if the daytime running lights need to be turned on or, if it’s darker out, the headlights. The sensor could be on the outside or the middle of the dash, and it probably looks like a half-dome. Our most popular Sensors products for the 2015 Chevrolet Traverse are: Autel 1-Sensor - 315 MHZ + 433 MHz from $44.99 Schrader Programmable, Multi Frequency (314.9, 315 & 433 MHz), TPMS EZ-sensor with Rubber Snap-in Valve from $53.99 VDO REDI-Sensor VDO Metal Clamp-in Stem REDI-Sensor from $59.99. To perform an instant update of the Ambient Temperature Sensor, simultaneously press and hold the Recirculation button and A/C button on the HVAC control head. (Fig. 13) It is also possible to perform the instant update by using a scan tool in the special function mode and selecting instant OST update.