GM 12450036
Brake Switch

You need to remove the accelerator pedal retaining nuts before pushing the pedal aside to access the stop lamp switch. Use both hands to turn the stop lamp switch counterclockwise and pull it forward until it releases from its position. Then detach the stop lamp switch electrical connector. Insert the stop lamp switch into the retainer after connecting its electrical connector to the same component. Attach and fasten the speed pedal to the dash panel using the retaining nuts which should be tightened to 10 n.m (89 lb in). Complete the stop lamp switch setup by dialing the control to desired position.

The brake light switch should be serviced by taking off the driver side sound insulator and then separating the electrical connection (5, 6). Turn the brake switch one quarter counterclockwise and pull it toward the rear of the vehicle to disconnect it. Insert the stop lamp switch into its place in the retainer and turn it clockwise one quarter turn so that the switch fits properly. Once you have reconnected the connector, adjust the stoplamp switch. In the end, put the sound insulator for the driver's side back in place.

Before changing the stop lamp switch you need to detach the left instrument panel panel and disconnect connections 3 and 4 to the switch. Adjust the stop lamp switch counter-clockwise to its travel stop then pull it out of the retainer to unhook it. Fit the stop lamp switch into the retainer while keeping the Brake Pedal connected to the power booster rod and maintaining its original position throughout the process without pressing the brake. Press the stop lamp switch into the retainer until its plunger fully enters the switch barrel by about 2-3 pounds of pressure to stop the Brake Pedal bracket from misaligning the switch. Move the stop lamp switch until it reaches the travel stop then push a thickness gauge between the switch barrel and Brake Pedal bracket for 0.0 and 2.0 mm (0.0 - 0.78 inches). Attach electrical cables to the stop lamp switch before repositioning the insulator panel for the left side.

The first step to replace the cruise release switch requires instrument panel (I/P) sound insulator removal. First detach the cruise control release switch from the switch retainer while rotating it in a counterclockwise direction. Turn off the power at the cruise control release switch electrical connector and then unfasten the switch retainer from its bracket position on the pedals. Uninstall the switch retainer onto the pedal bracket while using its indexing arrow for orientation if the part was previously removed. Hook up the cruise control release switch electrical connector after which you should refill the Brake Pedal until the system shows full release. Secure the cruise release switch in the retainer by rotating it clockwise until complete while keeping the switch plunger against the rubber bumper without letting the bracket or switch contact arm deflect the pedal. Use a meter to check the switch barrel to switch contact rubber bumper clearance and verify that it should not exceed 1.2 mm (0.047 inches). Commercial vehicles must open their cruise release switch and stop lamp and torque converter clutch (TCC) switch at 25.4 mm (1 in) pedal travel distance so these components open either at the same time or before any braking operation starts. Before cruise control activates its disengagement the Brake Pedal should travel a maximum of 25.4 mm (1 in). The final step of the service consists of reinstalling the i/p sound insulator.

To fix the Brake Light Switch you must start by taking off the driver side sound insulator and electrical connection. To remove the brake switch you need to grasp it at the handle and twist it 90 degrees in the counterclockwise direction while drawing it towards the back. You insert the stoplamp switch into the retainer until the switch body rests in place. Then push the Brake Pedal up against the internal stop until you secure the switch. Push the switch until it reaches 90 degrees clockwise then engage the electrical connection and adjust the stoplamp switch settings. Replace the last section of the driver's side sound dampener.

Before you replace the stop lamp switch you need to remove the left instrument panel (I/P) closeout/insulator panel. Release the two electrical connections at points 3 and 4 from the stop lamp switch before turning the switch counterclockwise to reach its travel limit and pulling it backward to free it from its holder. You can install the stop lamp switch when its rider faces the retainer with the Brake Pedal secured to the power booster rod; do not depress the Brake Pedal as you fit the switch in place. Press forward against the stop lamp switch until the plunger sinks 2 to 3 lbs deep into its housing to avoid misaligning this component with the Brake Pedal bracket. To position the stop lamp switch properly rotate it clockwise to its travel stop. You should find the minimum plunger distance range between 0.0 mm (0.0 in) and 2.0 mm (0.78 in) using a feeler gauge when the switch is 0.0 mm (0.0 in) from the Brake Pedal bracket to the stop lamp switch barrel. Reattach the electrical connectors to the stop lamp switch before reinserting the left side interior panel.

Rotate the switch counterclockwise until the travel stop is reached and pull it rearward to remove it from the brake pedal bracket.

Disconnect the electrical connections from the stop lamp switch.

Reconnect the wiring harness connector(s) and pull the brake or clutch pedal fully rearward against the pedal stop until no audible "clicks" are heard, allowing the switch to move in the retainer for adjustment.

Connect the electrical connector (5, 6).

Reinstall the left instrument panel insulator.

Use a feeler gauge to check that the minimum plunger extension is between 0.0 mm (0.0 in) and 2.0 mm (0.78 in) between the stop lamp switch barrel and the brake pedal bracket.

Grasp the stop lamp switch and turn it counterclockwise while pulling it toward the front of the vehicle to remove it, then disconnect the electrical connector.

First, remove the accelerator pedal retaining nuts and move the pedal aside.

Yes, adjust the switch as needed.

Check the switch barrel to switch contact rubber bumper clearance, which should not exceed 1.2 mm (0.047 in).

Reconnect the electrical connector, adjust the stoplamp switch, and finally, reinstall the driver's side sound insulator.

Remove the stop lamp switch from the brake pedal bracket.

Turn the switch 90 degrees clockwise to lock it into position.