Automatic Temperature Control Sensor
WARNING: This page is about a different car, the 1994 Mercury Grand Marquis and 1994 Ford Crown Victoria. However, it is still accessible from the selected car via links, so may be relevant.
On Crown Victoria, sensor is located behind instrument panel, above radio. On Grand Marquis, sensor is located behind instrument panel, directly above A/C control panel and clock. See Fig 1 . The sensor contains a thermistor whose resistance varies with temperature. The thermistor provides an input to control module.
The sensor also includes an aspirator tube and a foam inlet seal. The aspirator provides a very small vacuum to draw a continuous sampling of passenger compartment air across thermistor. Forced air is routed to sensor through a tube from blower stream, giving power to operate aspirator.