Inflatable Restraint Steering Wheel Module Coil Centering

WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: The new SIR coil assembly will be centered. Improper alignment of the SIR coil assembly may damage the unit, causing an inflatable restraint malfunction.

Verify the following conditions before centering the SIR coil:
- The wheels on the vehicle are straight ahead.
- The block tooth (1) of the steering shaft assembly is in the 12 o'clock position.
- The ignition switch is in the LOCK position.
  
  Fig 1: Identifying Block Tooth Of Steering Shaft
  Courtesy of GENERAL MOTORS CORP.
If the front (5) of the SIR coil has a centering window (4), and the back side (2) includes a spring service lock (1), perform the following steps:
1. 2.1. Hold the SIR coil with the face up.
2. 2.2. While depressing the spring service lock, rotate the coil hub clockwise until the coil ribbon stops.
3. 2.3. Rotate the coil hub slowly, counterclockwise, until the centering window appears yellow and both arrows (3) line up.
4. 2.4. Release spring service lock between the locking tab. The SIR coil is now centered.
5. 2.5. Align the centered SIR coil with the horn tower and slide onto the steering shaft assembly.
  
  Fig 2: SIR Coil Showing Front, Centering Window, Back Side, Spring Service Lock & Alignment Arrows
  Courtesy of GENERAL MOTORS CORP.
If the front (4) of the SIR coil has a centering window (3), and the back side (1) includes NO spring service lock, perform the following steps:
1. 3.1. Hold the SIR coil with the face up.
2. 3.2. Rotate the coil hub clockwise until the coil ribbon stops.
3. 3.3. Rotate the coil hub slowly, counterclockwise until the centering window appears yellow and both arrows (2) line up. This is the CENTER position.
4. 3.4. While holding the coil hub in the CENTER position, align the SIR coil with the horn tower and slide onto the steering shaft assembly.
  
  Fig 3: SIR Coil Showing, Front, Centering Window, Back Side & Alignment Arrows
  Courtesy of GENERAL MOTORS CORP.
If the front side (3) of the SIR coil has NO centering window, but the back side (2) includes a spring service lock (1), perform the following steps:
1. 4.1. Hold the SIR coil with the back side up.
2. 4.2. While depressing the spring service lock, rotate the coil hub in the direction of the arrow (4) until the coil ribbon stops.
3. 4.3. Still pressing the spring service lock, rotate the coil hub in the opposite direction 2 1/2 revolutions.
4. 4.4. Release the spring service lock between locking tabs. The SIR coil is now centered.
5. 4.5. Align the centered SIR coil with the horn tower and slide onto the steering shaft assembly.
  
  Fig 4: SIR Coil Showing Front, Back Side, Spring Service Lock & Arrow
  Courtesy of GENERAL MOTORS CORP.
For the front side (2) of the SIR coil has NO centering window, and the back side (1) includes NO spring service lock, perform the following steps:
1. 5.1. Hold the SIR coil with the face up.
2. 5.2. Rotate the coil hub in the direction of the arrow until the coil ribbon stops.
3. 5.3. Rotate the coil hub, slowly, counterclockwise, for 2 1/2 revolutions. This is the CENTER position.
4. 5.4. While maintaining the coil hub in the CENTER position, align the centered SIR coil with the horn tower and slide onto the steering shaft assembly.
  
  Fig 5: SIR Coil Showing Front, Back Side & Arrow
  Courtesy of GENERAL MOTORS CORP.