Relays and Sensors

Inside Air Temperature Sensor Description

The inside air temperature sensor is a temperature-sensitive resistor similar to the outside temperature sensor. As cabin air temperature increases, resistance decreases. As cabin air temperature decreases, resistance increases.

A fan located in the in-vehicle air temperature sensor housing continually draws passenger compartment air over the sensor. This condition increases the accuracy of the temperature reading.

The heater and A/C control module monitors the vehicle temperature signals and uses this information in order to help determine command signals.

Upper and Lower Outlet Temperature Sensors

The heater and A/C temperature sensors are used in order to monitor discharge temperatures from the heater and A/C outlets. These sensors are located in the heater and the A/C ducts. The heater and A/C control module monitors the discharge temperature sensors and uses this information in order to help determine command signals.

Ambient Outside Air Temperature Sensor Description

The ambient air temperature sensor is a temperature-sensitive resistor. The resistance of the ambient air temperature sensor varies inversely with the outside air temperature. As the outside air temperature increases, the resistance decreases. As the outside air temperature decreases, the resistance increases.

The heater and A/C control module monitors the outside temperature signal and uses this information in order to help determine command signals. The sensor will not update when the vehicle is traveling less than 5 mph.

Sun Load Sensor Description

The sun load sensor is a light-sensitive photo-diode that is used to monitor the heat load of the sun on the vehicle. The sensor is located in the defroster grille where the sunlight reaches the sensor. As the sunlight intensity increases, the conductivity of the sensor increases.

The heater and A/C control module monitors the sun load sensor and uses this information in order to vary the in-vehicle temperature in order to compensate for the increased solar heat.