Ambient Temperature Sensor / Switch HVAC: Description and Operation

The ambient temperature sensor is a variable resistor mounted to a bracket that is secured with a screw to the right side of the radiator yoke, behind the radiator grille and in front of the engine compartment.

For complete circuit diagrams refer to Wiring. The ambient temperature sensor cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.

The ambient temperature sensor is a variable resistor that operates on a five-volt reference signal sent to it by the A/C-heater control. The resistance in the sensor changes as temperature changes, changing the temperature sensor signal circuit voltage to the A/C-heater control. Based upon the resistance in the sensor, the A/C-heater control senses a specific voltage on the temperature sensor signal circuit, which it is programmed to correspond to a specific temperature.