Circuit Description
The ambient light sensor is a photo transistor that the output changes as the light level changes. The climate control panel module (CCP) determines the ambient light based on the voltage from the ambient light sensor. The CCP module controls the headlamp automatic, on/off and delayed off functions.
Conditions for Running the DTC
| • | The CCP is powered. |
| • | DTC B1327 is not current. |
Conditions for Setting the DTC
The feedback voltage is greater than 4.8V for greater than 2 seconds.
Action Taken When the DTC Sets
The CCP sets the ambient light status to DARK.
Conditions for Clearing the DTC
The CCP does not detect a voltage greater than the predetermined value during the diagnostic self test.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests the ambient light sensor signal circuit for an open, short to ground, or short to power.
-
This step tests the signal return circuit for an open or short to power.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Lighting Systems Diagnostic System Check? | -- | ||
2 |
Does the scan tool indicate the voltage is less than the specified value? | 4.8 V | ||
Does the voltage measure near the specified value? | 5 V | |||
Measure the voltage from the ambient light sensor signal circuit to the sensor return circuit. Does the voltage measure near the specified value? | 5 V | |||
5 | Test the ambient light sensor signal circuit for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
6 | Test the ambient light sensor return circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
7 | Inspect for poor connections at the ambient light sensor harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
8 | Inspect for poor connections at the CCP harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
9 | Replace the ambient light sensor. Refer to Sunload and Twilight Sentinel Sensor Replacement in Instrument Panel, Gauges and Console. Did you complete the replacement? | -- | -- | |
10 | Replace the CCP. Refer to Control Assembly Replacement in HVAC Systems - Manual. Did you complete the replacement? | -- | -- | |
11 | Operate the system in order to verify the repair. Did you find and correct the condition? | -- | System OK |
