B0348

CIRCUIT DESCRIPTION
The HVAC control module monitors the ambient light on the vehicle through a light sensitive photodiode which is called a sunload sensor. The HVAC control module uses this information to compensate for the effect of the sun on the inside air temperature of the vehicle. When the sunload sensor is in direct sunlight, the signal voltage is low. When the sunload sensor is shaded, the signal voltage is high. The HVAC control module requests A/C compressor clutch engagement and controls the air temperature actuator door positions in order to maintain the selected air temperature.

CONDITIONS FOR RUNNING THE DTC
The ignition is turned ON.

CONDITIONS FOR SETTING THE DTC
The HVAC control module detects the signal circuit is less than 0-09 V or greater than 4.90 V.

ACTION TAKEN WHEN THE DTC SETS
The system will default and assume no solar load is present.

CONDITIONS FOR CLEARING THE DTC
^ The DTC will become history if the HVAC control module no longer detects a failure.
^ The history DTC will clear after 50 fault free ignition cycles.
^ The DTC can be cleared with a scan tool.

DIAGNOSTIC AIDS
If condition not present refer to Testing for Intermittent and Poor Connections in Diagnostic Aids.

TEST DESCRIPTION

Steps 1-4:

Steps 5-12:

The numbers below refer to the step numbers on the diagnostic table.
2. The operating range of the sensor is between 0.09-4.90 volts. If the scan tool displays a value between 0-0.08 volt, or 4.91-5.0 volts, then the sensor is performing outside of its designed limits.
3. Tests for the proper operation of the circuit in the high voltage range.
4. Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.