Installation Procedure

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Attach the harness to the guide wire.
Using the guide wire, pull the lamp wire through the hole in the roof panel.
Remove the guide wire.
NOTE: 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.
Install the high mounted stop lamp (1) to the vehicle with the screws (2).
Tighten

Tighten the screws to 2 N.m (17 lb in).

Fig 1: Installing Procedure High Mounted Stop Lamp (Utility)

Courtesy of GENERAL MOTORS CORP.

Connect the electrical connector (4).
Install the headliner.
Install the left and right side rear window garnish molding.
Install the rear upper garnish molding. Refer to GARNISH MOLDING REPLACEMENT - REAR UPPER (AVALANCHE / ESCALADE EXT) or GARNISH MOLDING REPLACEMENT - REAR UPPER (TAHOE / YUKON / ESCALADE / SUBURBAN) in INTERIOR TRIM .