For 1990-2009 cars

The outside air temperature sensor is located on driver side front grille. In this position it is exposed to airflow through the grill. This provides a sample of the outside, ambient air temperature. The sensor is a thermistor used to control signal voltage to the heater and A/C control. The A/C control supplies a reference voltage, 5 volts to the sensor and measures voltage drop in the circuit to obtain a temperature signal. This signal is an input that tells the heater and A/C control how much cooling or heating will be required for passenger compartment. It also affects the mode and the blower speed.

When the outside, ambient air temperature is cold, thermistor resistance is high, therefore the heater and A/C control will receive a high signal voltage input. If air temperature is hot, thermistor resistance is low, and the A/C control will receive a low signal voltage input.

### DTC Parameters

• | The ignition is in the RUN position

• | YEL (Circuit 61) is shorted to ground, voltage stays or near zero.

• | The condition is present for 30 seconds

• | The counts are less than 10

### Diagnostic Aids

• | If there is a DTC in history or an intermittent condition, perform the test shown by wiggling wiring and connectors. This will cause malfunction to appear.

• | Visually inspect sensor connector and harness for damage, corrosion or water intrusion.

• | Inspect connector halves for poor mating or terminal not fully seated in the connector body -- backed out.

• | Inspect for adequate terminal tension, mis-routed harness, rubbed-through wire insulation and broken wire inside the insulation.

• | Inspect for improperly formed or damaged terminals. All connector terminals in the related circuit should be carefully reformed or replaced to ensure proper contact tension.