Diagnostic Instructions
DTC Descriptors
DTC B3888 02: Trailer Right Turn Signal Circuit - Short to Ground
DTC B3888 05: Trailer Right Turn Signal Circuit - Short to Battery or Open
Circuit/System Description
When the right turn signal switch is placed in the ON position, ground is applied to the auxiliary body control module (XBCM) through the turn signal lamp switch circuit. The XBCM then applies voltage on the trailer turn signal lamp circuit to the trailer
right turn signal lamp.
Conditions for Running the DTC
• | The right turn signal lamps must be ON and the right turn signal lamp must be commanded ON. |
Conditions for Setting the DTC
The body control module (BCM) detects an open, short to ground, or short to voltage on the trailer right turn signal lamp circuit while trying to apply a voltage to the circuit.
Action Taken When the DTC Sets
The trailer right turn signal lamp does not illuminate.
Conditions for Clearing the DTC
• | The conditions for setting the DTC are no longer present. |
• | A history DTC clears after 100 malfunction-free ignition cycles. |
• | The BCM receives the clear code command from the scan tool. |
Reference Information
Schematic Reference
Exterior Lights Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Ignition ON, activate with a scan tool the Trailer Right Turn Signal Lamp switch, trailer right turn signal lamp should illuminate.
Circuit/System Testing
- Inspect the trailer right turn signal lamp bulb for an open or shorted filament.
⇒ | If the bulb is inoperable, replace the bulb. |
- Turn signal lamp switch OFF. Clear the DTC. Test the trailer right turn signal lamp circuit for a short to voltage, short to ground, an open, or high resistance.
⇒ | If all circuits/connections test normal, replace the XBCM. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for XBCM replacement, setup, and programming