Ambient Temperature Sensor / Switch HVAC: Description and Operation

Ambient Sensor Circuit

COMPONENT DESCRIPTION

Ambient Sensor
The ambient sensor is attached on the ambient sensor bracket. It detects ambient temperature and converts it into a resistance value which is then input into the display and A/C auto amp.

AMBIENT TEMPERATURE INPUT PROCESS
The display and A/C auto amp. includes a processing circuit for the ambient sensor input. However, when the temperature detected by the ambient sensor increases quickly, the processing circuit retards the display and A/C auto amp. function. It only allows the display and A/C auto amp. to recognize an ambient temperature increase of 0.33 °C (0.6 °F) per 100 seconds.

As an example, consider stopping for a few minutes after high speed driving. Although the actual ambient temperature has not changed, the temperature detected by the ambient sensor will increase. This is because the heat from the engine compartment can radiate to the front grille area, location of the ambient sensor.