Chevrolet Silverado / GMC Sierra. Service manual — part 2802

REPAIR INSTRUCTIONS

TRAILER BRAKE CONTROL SWITCH REPLACEMENT

Fig. 3: View Of Trailer Brake Control Switch
Courtesy of GENERAL MOTORS CORP.

TRAILER BRAKE CONTROL MODULE REPLACEMENT

Callout

Component Name

Preliminary Procedure:
Remove the knee bolster. Refer to Knee Bolster Replacement (with RPO SLT) or Knee
Bolster Replacement (without RPO SLT)

1

Trailer Brake Control Switch

Procedure

1. Disconnect the electrical connectors.

2. Use a plastic flat bladed tool to release the switch from the knee bolster

trim.

2008 Chevrolet Silverado 1500

2008 BRAKES Trailer Brake Controls - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Fig. 4: View Of Trailer Brake Control Module & Bolts
Courtesy of GENERAL MOTORS CORP.

Callout

Component Name

Preliminary Procedures

1. Turn the ignition switch to the OFF position.

2. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .

1

Trailer Brake Control Module Bolt (Qty: 3)

Procedure:
Loosen, but do not remove the bolts. It is not necessary to completely remove
the bolts.

Tighten: 9 N.m (80 lb in)

NOTE:

Refer to Fastener Notice .

Trailer Brake Control Module

Procedure

2008 Chevrolet Silverado 1500

2008 BRAKES Trailer Brake Controls - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

TRAILER BRAKE CONTROL RELAY REPLACEMENT

Fig. 5: View Of Trailer Brake Control Relay, Electrical Connector & Bolts
Courtesy of GENERAL MOTORS CORP.

2

1. Disconnect the electrical connector.

2. Slide the module upward to remove.

3. If installing a new trailer brake control module, program the module.

Refer to Control Module References .

Callout

Component Name

Preliminary Procedures

1. Turn the ignition switch to the OFF position.

2. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .

1

Trailer Brake Control Relay Electrical Connector
Procedure:
Disconnect the electrical connector.

Trailer Brake Control Relay Bolt (Qty: 2)

NOTE:

Refer to Fastener Notice .

2008 Chevrolet Silverado 1500

2008 BRAKES Trailer Brake Controls - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

DESCRIPTION AND OPERATION

TRAILER BRAKE CONTROLS DESCRIPTION AND OPERATION

This vehicle may be equipped with a Trailer Brake Control (TBCM) system for electric trailer
brakes. The power output to the trailer brakes is based on the amount of brake pressure being
applied in the vehicle's brake system. The available power output to the trailer brakes can be
adjusted to a wide range of trailering situations.

The vehicle is equipped with the following trailer braking components:

Manual Trailer Brake Apply

Trailer Gain Adjustment

2

Procedure:
Loosen, but do not remove the bolts. It is not necessary to completely remove
the bolts.

Tighten: 9 N.m (80 lb in)

3

Trailer Brake Control Relay
Procedure:
Slide the relay upward to remove.

IMPORTANT: Connecting a trailer that is not compatible with the ITBC system

may result in reduced or complete loss of trailer braking. There
may be an increase in stopping distance or trailer instability
which could result in personal injury or damage to your vehicle,
trailer, or other property. An aftermarket controller may be
available for use with trailers with surge, air or electric-over-
hydraulic trailer brake systems. To determine the type of brakes
on your trailer and the availability of controllers, check with your
trailer manufacturer or dealer.

IMPORTANT: If your vehicle is equipped with an ITBC, the blunt cuts exist, but

are not connected further in the harness. If you install an
aftermarket trailer brake controller, the ITBC must be
disconnected. Do not power both ITBC and aftermarket
controllers to control the trailer brakes at the same time.

2008 Chevrolet Silverado 1500

2008 BRAKES Trailer Brake Controls - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado