1. Disconnect the negative battery cable.

Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

2. Remove tie straps.
3. Disconnect electrical connector.
4. Remove the air lines.

Refer to Trailer Coupling Hose and Line Bracket Replacement in Air Brakes.




5. Remove the two mounting bolts (2), four washers (3) and two nuts (5).
6. Remove the modulator (4).

Important: It may be necessary to transfer the fittings from the old modulator to the replacement part.

1. Install the modulator to vehicle using two mounting bolts (2), four washers (3) and two nuts (5).

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.

Tighten
Tighten the modulator nuts (5) to 70 N·m (52 lb ft).

2. Connect air lines to modulator valve.
3. Install the modulator electrical connector.
4. Install new tie straps.
5. Reconnect the negative battery cable.

Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.