Brake Light Switch

Replace the brake light switch located on the brake pedal assembly under the dash, which controls the brake lights and is critical for safe vehicle operation.

Warnings

Tools required

Parts

• Brake light switch × 1 — Use OEM specification

Preparation

1. Park vehicle on level ground and engage parking brake.
2. Turn ignition to OFF position and remove key.
3. Disconnect negative battery terminal to prevent electrical shorts while working. Use 10mm wrench or socket.
4. Allow at least 2 minutes after battery disconnect for airbag system capacitors to discharge.
5. Adjust driver's seat fully rearward to maximize working space under dash.
6. Position work light to illuminate brake pedal assembly area from driver's side footwell.

Procedure

1. 1

   Locate the brake light switch
   Lie on your back in the driver's footwell and look up at the brake pedal bracket. The brake light switch is mounted on the brake pedal bracket above the pedal arm. It is a cylindrical component with a plunger that contacts the brake pedal arm or a bracket near the pedal pivot. The electrical connector will be visible on the switch body.
2. 2

   Disconnect the electrical connector
   Locate the electrical connector on the brake light switch body. Press the locking tab on the connector (typically on top or side) and pull the connector straight off the switch. If access is tight, use needle-nose pliers to depress the locking tab while pulling. Note the connector orientation for reinstallation.
3. 3

   Remove the brake light switch
   The switch is typically retained by a quarter-turn bayonet mount or a threaded collar. For bayonet mount: rotate the switch body counterclockwise approximately 30 degrees and pull straight out from the bracket. For threaded type: rotate counterclockwise until the switch threads completely out of the mounting bracket. Note the installation depth and orientation of the switch plunger relative to the pedal arm for proper adjustment during reinstallation.
4. 4

   Inspect the mounting bracket and pedal contact point
   With the switch removed, inspect the mounting bracket for cracks or damage. Check the brake pedal arm contact surface for wear or debris. Clean any dirt or debris from the mounting hole and pedal contact area. Verify the pedal returns fully to the rest position without binding.
5. 5

   Prepare the new brake light switch
   Compare the new switch to the old switch to verify correct replacement part. Check that the connector type, mounting style, and plunger length match. Some switches come with the plunger in a retracted or shipping position that will automatically adjust on first pedal application.
6. 6

   Install the new brake light switch
   Insert the new switch into the mounting bracket, aligning the tabs or threads. For bayonet mount: push the switch fully into the bracket and rotate clockwise approximately 30 degrees until it locks. For threaded type: thread clockwise by hand until snug, positioning the switch so the plunger just contacts the brake pedal arm in the rest position. Do not overtighten threaded switches as the housing may crack.
7. 7

   Adjust switch position if applicable
   With the brake pedal in the fully released rest position, verify the switch plunger is compressed approximately 1-3mm by the pedal or pedal bracket, holding the brake-light contacts open (lights OFF). This ensures the switch closes and turns the lights ON immediately when the pedal is depressed. If the switch has an adjustment collar, rotate it to achieve proper plunger preload. Self-adjusting switches will set themselves on first pedal application.
8. 8

   Reconnect the electrical connector
   Push the electrical connector firmly onto the switch terminals until the locking tab clicks into place. Tug gently on the connector to verify it is fully seated and locked. Ensure the wiring is not pinched between any moving pedal components or sharp edges.
9. 9

   Reconnect the battery
   Reconnect the negative battery terminal and tighten to secure. Use 10mm wrench or socket.
10. 10

    Test brake light operation
    Turn the ignition to ON position (engine does not need to run). Have an assistant observe the rear brake lights or position a mirror or reflective surface behind the vehicle. Press the brake pedal slowly and verify both brake lights illuminate immediately with minimal pedal travel. Release the pedal and verify lights turn off completely. Repeat the test 5 times to ensure consistent operation. If lights do not function correctly, recheck switch installation and adjustment.

Reassembly

1. Return driver's seat to normal operating position.
2. Clear all tools and parts from the driver's footwell before operating vehicle.

Verification

• With ignition ON, press brake pedal and verify both rear brake lights illuminate immediately.
• Verify brake lights turn off completely when pedal is released.
• Check that center high-mount stop lamp (CHMSL) also illuminates with brake pedal application.
• If equipped with cruise control, verify cruise control disengages when brake pedal is pressed (switch may also control cruise cancel function).
• Test drive in a safe area and verify brake lights function normally during actual braking.
• Have a following driver or assistant confirm brake lights are visible and functioning before returning to normal traffic.

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