GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2008 🢒 Astra 🢒 Body Systems 🢒 Lighting 🢒 DTC B3634-B3636, B3650-B3652, or B3840

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.

DTC Descriptors

DTC B3634 5a: Left Turn Signal Switch (F1) Stuck

DTC B3635 5a: Right Turn Signal Switch (F2) Stuck

DTC B3636 5a: Left Turn Signal Switch (F2) Stuck

DTC B3650 5a: Highbeam Switch Stuck

DTC B3651 5a: Headlamp Flasher Switch Stuck

DTC B3652 5a: Right Turn Signal Switch (F1) Stuck

DTC B3840 00: Wrong Stalk Switch Configuration

Circuit/System Description

The turn signal/multifunction switch is integrated into the steering column module. The turn signal/multifunction switch contains functions that control the headlamp dimming functions, left and right turn signals, and flash to pass. When either of these switches is activated, the steering column module interprets the position of the switch and sends a serial data message to the underhood electrical center (UEC) or the rear electrical center (REC) requesting the appropriate functions be activated. The steering column module also sends a serial data message to the instrument panel cluster (IPC) requesting the appropriate indicator be illuminated for the function being requested.

Conditions for Running the DTC

Battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

DTC B3634 5a through DTC B3652 5a

These DTCs will set when the steering column module detects a switch is stuck or applied for greater than 60 seconds.

DTC B3840 00

The DTC will set when the steering column module detects an incorrect switch configuration or the steering wheel control module was not programmed correctly.

Actions Taken When the DTC Sets

The steering column module will disable the switch function that has a fault present.

Conditions for Clearing the DTC
    • The condition responsible for setting the DTC no longer exists.
    • A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

DTC B3634 5a through DTC B3652 5a

  1. Ignition ON, with a scan tool, perform the Reset the ECU function located in programming for the steering column module.
  2. Operate the turn signal/multifunction switch function within the conditions for running the DTC, verify the DTC does not reset.
    3. ⇒If the DTC resets, replace the steering column module.

DTC B3840 00

  1. Ignition ON, with a scan tool, perform the Program Variant Configuration located in programming for the steering column module.
  2. Ignition ON, with a scan tool, perform the Reset the ECU function located in programming for the steering column module.
  3. Operate the turn signal/multifunction switch function within the conditions for running the DTC, verify the DTC does not reset.
    4. ⇒If the DTC resets, replace the steering column module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Steering Column Module replacement, setup, and programming