Power Trunk / Liftgate Hazard Sensor: Description and Operation
PINCH SENSORS/THERMISTORDESCRIPTION
Pinch sensors (2) are located on each side of the lift-gate (1). These sensors look like weather-strips, however they consist of pieces of electrically conductive rubber (tapeswitch), wires, resistor, double sided tape, and a plastic carrier. They are used to indicate an obstruction during a power liftgate close cycle. The right side pinch sensor contains a thermistor that is integral to the pinch sensor assembly. The thermistor is a temperature sensor used by the power liftgate control module to enable proper liftgate operation in extreme climate conditions.
OPERATION
During a power liftgate "close" cycle, if either of the two conductive rubber strips (tapeswitch) of the pinch sensor come in contact with an obstacle, the pinch sensor circuit is completed. This tells the power liftgate control module that a obstruction is felt. The control module will stop the liftgate immediately and return it to the full open position. The thermistor portion of the right pinch sensor provides the temperature signal to the power liftgate control module (temperature is provided when the pinch sensor is in an unpinched condition; when pinched, temperature is unavailable because the thermistor is shorted). As the outside temperature increases, the resistance reading decreases. As temperature decreases, the resistance reading increases.