Installation Procedure

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 Chevrolet Avalanche, 2003 Cadillac Escalade EXT, and 2003 Cadillac Escalade ESV. However, it is still accessible from the selected car via links, so may be relevant.

IMPORTANT: Use the Threadlocker, GM P/N 12345382 (Canadian P/N 10953489), to all bolt threads prior to assembly.

Install the assist step brackets to the vehicle (4).
Install the bolts (6) to the brackets and ensure that the brackets are seated securely to the inner rocker panel.
Install the heater and A/C tubes retaining nuts to the studs, if equipped. Refer to HEATER PIPE REPLACEMENT -- AUXILIARY in Heating, Ventilation, and Air Conditioning.
With the aid of an assistant, install the assist step to the vehicle.
Install the bolts (1, 5) and the nuts (2, 3) to the assist step bracket, and leave the nuts loose.

Fig 1: Installing Bolts And Nuts To Assist Step Bracket
Courtesy of GENERAL MOTORS CORP.

NOTE: Refer to FASTENER NOTICE in GM VEHICLES CAUTIONS & NOTICES .
Install the bottom fender bolt (2) and the washer (1) to the vehicle.
Tighten

Tighten the bottom fender bolt (2) to 25 N.m (18 1b ft).

Fig 2: Installing Bottom Fender Bolt And Washer To Vehicle
Courtesy of GENERAL MOTORS CORP.
Tighten the assist step fasteners in the following sequence:
Tighten
1. 7.1. Tighten the bracket bolt (6) to 25 N.m (18 1b ft).
2. 7.2. Tighten the assist step bracket nut (2) to 9 N.m (80 lb in).
3. 7.3. Tighten the assist step to the bracket nut (3) to 9 N.m (80 lb in).
  
  Fig 3: Tightening Assist Step Fasteners
  Courtesy of GENERAL MOTORS CORP.
Install the assist step rear cover to the vehicle.
Install the clip retainer.

Fig 4: Installing Assist Step Rear Cover To Vehicle
Courtesy of GENERAL MOTORS CORP.
Install the assist step front cover to the vehicle.
Install the push-in retainer.

Fig 5: Installing Push-In Retainer
Courtesy of GENERAL MOTORS CORP.