GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B0183 02: Solar Load Sensor 1 Circuit Short to Ground

DTC B0183 05: Solar Load Sensor 1 Circuit Short to Battery or Open

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Ambient Air Temperature Sensor Signal

B0158 02

B0158 05

B0158 05

1

Upper Air Temperature Sensor Signal

B0173 06

B0173 05

B0173 05

1

Lower Air Temperature Sensor Signal

B0178 06

B0178 05

B0178 05

1

Sunload Sensor Signal

B0183 02

B0183 05

B0183 05

1

Ambient Air Temperature Sensor Low Reference

--

B0158 05

--

--

Upper Air Temperature Sensor Low Reference

--

B0173 05

--

--

Lower Air Temperature Sensor Low Reference

--

B0178 05

--

--

Sunload Sensor Low Reference

--

B0183 05

--

--

Sunload Sensor Ground

--

B0183 05

--

--

1. Air Temperature Malfunction

Circuit Description

The sunload sensor is a 2-wire photo diode. The vehicle uses a single sunload sensor. The sensor is integrated into the sunload sensor assembly along with the ambient light sensor. Body ground and signal circuits enable the sensor to operate. As the sunload increases, the sensor signal decreases. The sensor operates within an intensity range between completely dark and very bright. The sensor signal varies between 0-5 volts. The body control module (BCM) converts the signal to a range between 0-255 counts. The sunload sensor provides the HVAC control module with a measurement of the amount of light shining on the vehicle. Bright or high intensity light causes the vehicles interior temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle.

Conditions for Running the DTC

Ignition ON.

Conditions for Setting the DTC

The BCM detects the signal circuit is less than 0.09 volt (5 counts) or greater than 4.90 volts (250 counts).

Action Taken When the DTC Sets

The HVAC control module will operate the system as if no sunload condition exists.

Conditions for Clearing the DTC

    • The DTC will become history if the BCM no longer detects the condition that set the DTC.
    • The history DTC will clear after 50 fault-free ignition cycles.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

    •  Air Temperature Description and Operation
    •  Air Delivery Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool Sunload Sensor parameter. The reading should be between 5-250 counts and change with sunlight changes.

Circuit/System Testing

Important: If a solar load sensor has an out of range condition caused by a short to voltage, short to ground, or an open/high resistance, the scan tool will display the same value: 225 counts.

  1. Ignition OFF, disconnect the harness connector at the sunload sensor.
  2. Test for less than 10 ohms between the ground circuit terminal C and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, test for 4.8-5.2 volts between the ground circuit terminal C and the signal circuit terminal A.
  5. If less than the specified range, test the signal circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the BCM.
    If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  6. If all circuits test normal, test or replace the sunload sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Ambient Light Sensor Replacement
    •  Control Module References for BCM and HVAC control module replacement, setup, and programming