For 1990-2009 cars

### Removal Procedure

1. Apply the parking brake.
2. Block the wheels.
3. Drain all of the air reservoirs. Refer to Air Brake Reservoir Draining .
4. Disconnect the inter-axle differential lock switch air lines. Refer to Hose and Line Replacement - Nylon Push-In Type Fitting .
5. Remove the inner axle differential lock switch retaining nut.
6. Remove the inter-axle differential lock switch.

### Installation Procedure

1. Install the inter-axle differential lock switch.

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 inner axle lock switch retaining nut.

Tighten
Tighten the inter-axle differential lock switch to 28 N·m (21 lb ft).

3. Connect the inter-axle differential lock switch air lines. Refer to Hose and Line Replacement - Nylon Push-In Type Fitting .
4. Start the engine. Charge the system to the air compressor governor cut out point.
5. Stop the engine.
6. Inspect for air leaks.
7. Remove the wheel blocks.