1. Raise and suitably support the vehicle, if required. Refer to Lifting and Jacking the Vehicle in General Information.
2. If equipped with the 6.6L or 7.2L engine, with regular production options (RPOs) MK0/MPU/MM7/MSC and MWW, disconnect the backup lamp switch electrical connector.



3. If equipped with the 8.1L engine, with RPOs MSC/MPU, disconnect the backup lamp switch electrical connector.
4. Remove the backup lamp switch.

Important: A NEW backup lamp switch has pre-applied thread sealant on the threads.

1. If installing the old backup lamp switch, apply thread sealant GM P/N 12346004, (Canadian  P/N 10953480) or equivalent to the threads.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

2. Install the backup lamp switch.

Tighten
Tighten the backup lamp switch to 48 N·m (35 lb ft).

3. If equipped with the 8.1L engine, with RPOs MSC/MPU, connect the backup lamp switch electrical connector.



4. If equipped with the 6.6L or 7.2L engine, with RPOs MK0/MPU/MM7/MSC and MWW, connect the backup lamp switch electrical connector.
5. Lower the vehicle, if required.