Circuit Description
When the turn signal/multifunction switch is placed in the left turn position, ground is applied to the body control module (BCM) through the left turn signal switch circuit. The BCM then applies a pulsating voltage to the LF and LR turn signal lamps through the LF and LR turn signal voltage supply circuits.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B3950 Left Rear Turn Signal Circuit
DTC Symptom | DTC Symptom Descriptor |
|---|---|
02 | Short to Ground |
05 | Open or Short to Voltage |
Conditions for Running the DTC
Battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
| • | DTC B3950 02 will set when the BCM detects a short to ground in the LR turn signal voltage supply circuit. |
| • | DTC B3950 05 will set when the BCM detects an open or short to voltage in the LR turn signal voltage supply circuit. |
Action Taken When the DTC Sets
| • | When DTC B3950 02 is present, the LR turn signal lamp will not operate. |
| • | When DTC B3950 05 is present, the LR turn signal lamp will be ON at all times for a short to voltage condition. For an open condition, the LR turn signal lamp will be inoperative. |
Conditions for Clearing the DTC
| • | The condition responsible for setting the DTC no longer exists. |
| • | You issue a scan tool CLEAR DTCs command. |
| • | A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred. |
Diagnostic Aids
Check the LR turn signal bulb. If the bulb is open, DTC B3950 05 will set as current only.
Thoroughly inspect the wiring and connectors. An incomplete inspection of the wiring and connectors may result in misdiagnosis causing part replacement with the reappearance of the malfunction. If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections .
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Exterior Lights Schematics Connector End View Reference: Master Electrical Component List | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 |
Is DTC B3950 02 present? | Go to Step 3 | Go to Step 4 |
3 |
Does the test lamp illuminate? | Go to Step 8 | Go to Step 10 |
4 | Is the LR turn signal lamp ON at all times? | Go to Step 5 | Go to Step 6 |
5 |
Does the LR turn signal lamp turn OFF? | Go to Step 10 | Go to Step 7 |
6 |
Does the test lamp illuminate? | Go to Step 10 | Go to Step 9 |
7 | Locate and repair a short to battery voltage in the LR turn signal lamp voltage supply circuit. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 12 | -- |
8 | Locate and repair a short to ground in the LR turn signal lamp voltage supply circuit. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 12 | -- |
9 | Locate and repair an open or high resistance in the LR turn signal lamp voltage supply circuit. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 12 | -- |
10 | Inspect for poor connections at the C3 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 |
11 | Replace the BCM. Refer to Control Module References 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 |
