This procedure replaces the brake light switch, which activates the brake lights when the brake pedal is pressed and signals the engine control system.

Warnings

Tools required

Parts

• Brake light switch × 1 — Motorcraft SW-6930 or equivalent

Preparation

1. Park vehicle on level ground and apply parking brake
2. Turn ignition to OFF position and remove key (or ensure push-button start is completely off)
3. Open driver's door and ensure interior lighting is adequate for working under the dash
4. Adjust driver's seat fully rearward for maximum working space
5. Disconnect negative battery terminal and wait 2 minutes to allow capacitive discharge (prevents accidental airbag deployment while working near steering column)

Procedure

1. 1

   Access the brake pedal assembly
   Position yourself in the driver's footwell on your back, looking up at the brake pedal assembly. Use a flashlight to locate the brake light switch, which is mounted on a bracket above the brake pedal arm. The switch has a plunger that contacts the pedal arm when released.
2. 2

   Disconnect the electrical connector
   Locate the electrical connector on the brake light switch. Press the locking tab on the connector while pulling it straight away from the switch body. If the connector is tight, use a flathead screwdriver to gently pry the locking tab while pulling. Note the connector orientation for reassembly.
3. 3

   Remove the old brake light switch
   The switch uses a quarter-turn or push-and-rotate locking mechanism. Rotate the switch body counterclockwise approximately 30-45 degrees while pulling outward from the mounting bracket. If the switch is difficult to rotate, gently rock it side-to-side while turning. The switch should release from the bracket and can be pulled free.
4. 4

   Inspect the mounting bracket
   Examine the mounting bracket for cracks or damage. Check that the retaining clips inside the bracket are intact. Clean any dirt or debris from the bracket opening using a clean cloth.
5. 5

   Prepare the new switch
   Compare the new brake light switch to the old unit to verify correct replacement part. Note the position of the plunger - it should be fully extended on the new switch. Do not press the plunger in before installation, as this pre-loads the switch for proper adjustment during installation.
6. 6

   Install the new brake light switch
   Insert the new switch into the mounting bracket with the plunger facing toward the brake pedal arm. The switch should slide into the bracket until it stops. While maintaining inward pressure, rotate the switch body clockwise approximately 30-45 degrees until it locks into place. You should feel or hear a click when properly seated.
7. 7

   Connect the electrical connector
   Push the electrical connector onto the switch terminals until the locking tab clicks into place. Gently tug on the connector to verify it is fully locked. Ensure the wiring is not pinched or stretched.
8. 8

   Reconnect the battery
   Reconnect the negative battery terminal. The switch is now installed and the system will self-adjust when the brake pedal is first pressed.

Reassembly

1. Return driver's seat to normal position
2. Ensure no tools or parts are left in the footwell area

Verification

• Turn ignition to ON position without starting the engine
• Verify the brake lights are OFF with the pedal released
• Press the brake pedal and have an assistant confirm both brake lights illuminate (or observe reflection in a wall/window)
• Release the pedal and verify lights turn OFF
• On vehicles with push-button start: verify the engine will only start with brake pedal pressed
• On vehicles with automatic transmission: verify the shifter will not move out of PARK without the brake pedal pressed
• Test drive in a safe area and verify cruise control functions properly (if equipped)
• If brake lights do not function correctly, check for diagnostic trouble codes and verify switch installation orientation

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