GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Driveline/Axle 🢒 Drive Axle - Locking/Limited Slip 🢒 Differential Lock Switch Replacement

Removal Procedure
  1. Apply the parking brake.
  2. Block the vehicle wheels.
  3. Drain all of the air reservoirs. Refer to Air Brake Reservoir Draining .

    4. Important: Tag the air lines for later installation.

  4. Remove the air lines at the differential lock control valve. Refer to Hose and Line Replacement - Nylon Push-In Type Fitting .
  5. Disconnect the wiring harness connector.

    6. Object Number: 1549000 Size: SH
  6. Remove the differential lock switch (2) from the air brake supply manifold (1).

Installation Procedure

    Object Number: 1549000 Size: SH
  1. Install the differential lock control valve (2) to the air brake supply manifold (1).
  2. Connect the wiring harness connector.
  3. Install the air lines at the differential lock control valve. Refer to Hose and Line Replacement - Nylon Push-In Type Fitting .
  4. Start the engine.
  5. Inspect for air leaks. Refer to Air Brake System Testing .
  6. Verify proper operation of the inter-axle differential lock.
  7. Remove the wheel blocks.