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For 1990-2009 cars only
Makes 🢒 HUMMER 🢒 2007 🢒 H2 🢒 Driver Information and Entertainment 🢒 Cellular, Entertainment, and Navigation 🢒 DTC B0183 or B0188

Circuit Description

The following DTCs are for the left and right sunload sensors.

    • B0183 is for the left sunload sensor.
    • B0188 is for the right sunload sensor.

The left and right sunload sensors provide the HVAC control module with inputs as to the amount heat load the sun is placing on the interior of the vehicle. The sunload sensors are photodiodes that are sensitive to light intensity. The body control module (BCM) applies 5 volts to internal input resistors that are connected to the left and right signal circuits of the sunload sensor assembly. The BCM provides ground to the sensors through the low reference circuit. The BCM monitors the voltage drops across the sunload sensors and converts the voltage values to count values where 1 volt is approximately equal to 51 counts. As the light intensity increases, the sunload sensors allow more current to travel through the circuits and the signal voltages decrease. As the light intensity decreases, the sunload sensors allow less current to travel through the circuits and the signal voltages increase. The BCM transmits the data to the HVAC control module over the class 2 serial data circuit.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

    • DTC B0183 Solar Load Sensor 1 Circuit
    • DTC B0188 Solar Load Sensor 2 Circuit

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The BCM determines that the value of the sunload sensor signal is less than 5 counts or greater than 250 counts.

Action Taken When the DTC Sets

The action taken will be for the BCM to revert to a calibrated default value.

Conditions for Clearing the DTC
    • The DTC will become history if the BCM no longer detects a failure.
    • The history DTC will clear after 100 fault-free ignition cycles.
    • The DTC can be cleared with a scan tool.

Diagnostic Aids

If condition not present, refer to Testing for Intermittent Conditions and Poor Connections .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step verifies that the value displayed is within the specified range.

    2.

  2. This step tests for the proper operation of the circuit in the high voltage range.

    3.

  3. This step 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.

Step

Action

Value(s)

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the appropriate Solar Sensor parameter in the body control module (BCM) data list. Refer to one of the following parameters:
    4. • Left Solar Sensor
    • Right Solar Sensor

Does the scan tool indicate that the appropriate Solar Sensor parameter is within the specified range?

5-250 Counts

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the sunload sensor assembly.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the appropriate Solar Sensor data parameter.

Does the scan tool indicate that the appropriate Solar Sensor parameter is greater than the specified value?

250 Counts

Go to Step 4

Go to Step 5

4

  1. Turn OFF the ignition.
  2. Connect a 3-amp fused jumper wire between the signal circuit of the sunload sensor assembly and the low reference circuit of the sunload sensor assembly.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the appropriate Solar Sensor parameter.

Does the scan tool indicate that the appropriate Solar Sensor parameter is less than the specified value?

5 Counts

Go to Step 8

Go to Step 6

5

Test the solar signal circuit of the sunload sensor assembly for a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

6

Test the signal circuit of the sunload sensor assembly for a short to voltage, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 12

Go to Step 7

7

Test the low reference circuit of the sunload sensor assembly for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

8

Inspect for poor connections at the harness connector of the sunload sensor assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 12

Go to Step 10

9

Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 12

Go to Step 11

10

Replace the sunload sensor assembly. Refer to Sun Load Sensor Replacement .

Did you complete the replacement?

--

Go to Step 12

--

11

Replace the BCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 12

--

12
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC, as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK