GM Service Manual Online
For 1990-2009 cars only

The temperature sensor is mounted to the hood latch support bracket near the center of the grille opening. A two-wire weather pack electrical connector connects the sensor to the headlamp harness. The sensor itself is a thermistor which provides resistance that varies with temperature. If a defective thermistor is suspected, use an ohmmeter to measure the resistance of the sensor. Disconnect the sensor from the wiring harness to conduct the measurement. The correct resistance values for the sensor are shown in Sensor Resistance Table .

The electronics module has the capability of detecting a short circuit or an open circuit in the temperature sensor circuitry. The module will display an SC in the temperature display field if a short circuit is detected, or an OC if an open circuit is detected. If either an SC or an OC is displayed, inspect the wire harness between the sensor and the electronic module. The short or the open will be located in this area.