Circuit Description
The HVAC control module (IPM) monitors the ambient light on the left and right side of the vehicle through a light sensitive photodiode called a sunload sensor assembly. 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 sensor is in direct sunlight, the signal voltage is low. When the 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 on the HVAC control module.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC B0184 Solar Load Sensor Left |
| • | DTC B0189 Solar Load Sensor Right |
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 5 counts ( 0.09 V) or greater than 250 counts (4.90 V).
Action Taken When the DTC Sets
A default value will be used for the sensor data by the HVAC control module. The Solar Sensor displayed on the scan tool in the Instrument Panel Module (IPM) HVAC Sensors data list will be the default value. The Solar Sensor displayed on the scan tool in the Instrument Panel Module Open/Short Data list will be the actual value.
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 Conditions and Poor Connections in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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When diagnosing using this table, DTC B0184 is for the left sunload sensor. DTC B0189 is for the right sunload sensor. Follow table for corresponding circuits for that DTC.
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Tests for the proper operation of the circuit in the high voltage range.
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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 | Values | 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 in Vehicle DTC Information |
Does the scan tool indicate that the Solar Sensor parameter is with in the specified range? | 0.09-4.90 V | Go to Diagnostic Aids | Go to Step 3 | |
Does the scan tool indicate that the Solar Sensor parameter is greater than the specified value? | 4.90 V | Go to Step 4 | Go to Step 5 | |
Does the scan tool indicate that the Solar Sensor parameter is less than the specified value? | 0.09 V | Go to Step 8 | Go to Step 6 | |
5 | Test the signal circuit of the sunload sensor assembly for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. 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 in Wiring Systems. 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 in Wiring Systems. 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 in Wiring Systems. 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 HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. 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 HVAC control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 12 | -- |
12 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
