The sunload sensor is a 2-wire photo diode. The vehicle uses left and right sunload sensors. The two sensors are integrated into the sunload sensor assembly along with the ambient light sensor. Low reference and signal circuits enable the sensor to operate. As the sunload increases, the sensor signal decreases. The sensor signal varies between 0-5 volts. The HVAC control module converts the signal to a range between 0-255 counts. The sunload sensor provides the HVAC control module a measurement of the amount of light shining on the vehicle. Bright or high intensity light causes the vehicles inside temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the passenger compartment.

The ignition is ON.

The HVAC control module detects the signal circuit is less than 0.09 volt (5 counts) or more than 4.90 volts (250 counts).

If the DTC sets due to a low voltage condition, the HVAC control module will operate the system as if a maximum sunload condition exists. If the DTC sets due to a high voltage condition, the HVAC control module will operate the system as if a minimum sunload condition exists.

Schematic Reference

HVAC Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connector at the sunload sensor assembly.
2. Test for less than 1.0 ohm of resistance between the ground circuit terminal C and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify the sunload sensor parameter is greater than 250 counts.

⇒	If not the specified value, test the appropriate signal circuit terminal A or B for a short to ground. If the circuit tests normal, replace the HVAC control module.

4. Install a 3A fused jumper wire between ground circuit terminal C and the appropriate signal circuit terminal of the sensor listed below. Verify the appropriate sunload sensor parameter is less than 5 counts.

•	Sunload sensor circuit terminal A.

•	Sunload sensor circuit terminal B.

⇒	If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.

5. If all circuits test normal, replace the sunload sensor assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.