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DTC B3950 or B3951 > < Reading Lamps Malfunction

Astra J

Hazard Lamps Malfunction

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.

Diagnostic Fault Information



Circuit
Short to Ground
Open/High Resistance
Short to Voltage
Signal Performance

Hazard Lamps Request Signal
2
1
1
B3596 00

Hazard Warning Switch Indicator Signal
3
3
4
-

Interior Backlighting Control
6
6
5
-

Hazard Switch Ground
-
1
-
-

1. Hazard lamps inoperative

2. Hazard lamps always ON

3. Hazard warning switch indicator inoperative

4. Hazard warning switch always ON

5. Hazard backlighting at full intensity and cannot be dimmed

6. Hazard backlighting does not illuminate
 

Circuit/System Description

The hazard flashers may be activated in any power mode. The hazard switch is permanently grounded. When the hazard switch is placed in the ON position, ground is applied through the hazard switch signal circuit to the body control module (BCM). The BCM supplies battery voltage to all turn signal lamps in an ON and OFF duty cycle. When the hazard switch is activated, the BCM sends a serial data message to the instrument cluster requesting both turn signal indicators to be cycled ON and OFF.

Reference Information


Schematic Reference


Connector End View Reference

Component Connector End Views


Description and Operation

Exterior Lighting Systems Description and Operation


Electrical Information Reference


Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

•  Ignition ON, perform the scan tool Hazard Lamps Switch parameter. The reading should change between Active/Inactive when changing between pressed and released hazard lamps switch button.
⇒ If not change between Active and Inactive, refer to Hazard Lamps Switch Malfunction.
•  Ignition ON, perform the Hazard Lamps Switch Backlight test. The Hazard Switch Indicator should be ON/OFF when changing between the commanded states.
⇒ If not change between ON and OFF, refer to Hazard Switch Indicator Malfunction.
•  Ignition ON, perform the instrument cluster All Indicators test ON and OFF test. Both turn signal indicators should be ON/OFF.
⇒ If not change between ON and OFF, refer to Hazard Lamp Indicators Malfunction.

Circuit/System Testing

Hazard Lamps Switch Malfunction

1. Ignition OFF
2. Disconnect the harness connector at the S26 Hazard Warning Switch.
3. Disconnect the negative terminal of the C1 Battery.
4. Test for less than 5 Ω between the S26 Hazard Warning Switch harness connector ground circuit terminal 7 and ground.
⇒ If greater than the specified value, test the ground circuit for an open/high resistance.
5. Reconnect the negative terminal of the C1 Battery.
6. Ignition ON, verify the scan tool Hazard Lamp Switch parameter is INACTIVE.
⇒ If not the specified value, test the signal circuit terminal 10 for a short to ground. If the circuit tests normal, replace the K9 Body Control Module.
7. Install a 3 A fused jumper wire between the signal circuit terminal 10 and ground. Verify the scan tool Hazard Lamp Switch parameter is ACTIVE.
⇒ If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.
8. If all circuits test normal, replace the S26 Hazard Warning Switch.

Hazard Switch Indicator Malfunction

1. Ignition OFF
2. Disconnect the harness connector at the appropriate inoperative accent light component.
3. Disconnect the negative terminal of the C1 Battery.
4. Test for less than 5.0 Ω between the ground circuit terminal 7 and ground.
⇒ If greater than the specified range, test the ground circuit for an open/high resistance.
5. Reconnect the negative terminal of the C1 Battery.
6. Connect a test lamp between the backlight control circuit terminal 5 and ground.
7. Ignition ON, command the Hazard Lamps Switch Backlight test ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
⇒ If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.
⇒ If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module.
8. If all circuits test normal, test or replace the appropriate component with the S26 Hazard Warning Switch.

Hazard Lamp Indicators Malfunction

1. Ignition ON
2. Command the All Indicators test ON and OFF with the scan tool, verify both turn signal indicators changes between turn ON and OFF.
⇒ If both turn signal indicators changes between illuminate and not illuminate during the test, replace the K9 Body Control Module.
⇒ If one or both turn signal indicators do not illuminate during the test or remain illuminated at all times, replace the P16 Instrument Cluster.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•  Control Module References for BCM or instrument cluster replacement, programming and setup

DTC B3950 or B3951 > < Reading Lamps Malfunction