Circuit/System Description

WARNING: This page is about a different car, the 2010 Pontiac G5 and 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.

The body control module (BCM) monitors the outside air temperature sensor to display outside air temperature. The temperature sensor is a 2-wire negative temperature co-efficient thermistor. The BCM applies 5 volts to an internal input resistor that is connected to the signal circuits of the outside air temperature sensor. The BCM provides the ground to the outside air temperature sensor through the low reference circuit. When the outside air temperatures are cold, the resistance of the sensor is high and the voltage signals are high. When the outside air temperatures are hot; the resistance of the sensor is low and the voltage signal is low. The BCM converts the voltage value to a temperature value of Celsius and Fahrenheit that will be displayed by the instrument panel cluster (IPC).