Brake light switch issue

DANJS1123

MEMBER
2014 FORD FIESTA
1.8L
4 CYL
2WD
AUTOMATIC
65,000 MILES

I had to remove the brake light switch to do another repair. When I reinstall the switch and then start the car, the brakes are locked and the car won't move. If I twist the switch out of the bracket, relieving the contact with the brake arm, everything is back to normal - e.G brakes work normal and brake lights normal. Also, with the switch mounted, the brake lights stay illuminated. Any ideas?

1 Reply

BMDOUBLE

MECHANIC
1,139 POSTS

The brake pedal position switch can be easily damaged and has to be adjusted using a scan tool. Here are the actual instructions so you can reference:

Brake Pedal Position (BPP) Switch Adjustment

Adjustment
NOTICE: Do not press the brake pedal when installing or removing the brake pedal position switch or damage to the brake pedal-mounted switches can occur.

1. Inspect all brake pedal position switches and brake pedal assembly to verify there is no brake pedal pressure unintentionally applied due to incorrect brake pedal position switch or brake pedal installation. Correct any concerns before proceeding to the next step.

2. Remove the driver knee airbag.
Refer to: Driver Knee Airbag See: Air Bag > Removal and Replacement (501-20B Supplemental Restraint System, Removal and Installation).

3. Confirm that all brake pedal and bracket assembly fasteners are correctly tightened.

4. Install the driver knee airbag.
Refer to: Driver Knee Airbag See: Air Bag > Removal and Replacement (501-20B Supplemental Restraint System, Removal and Installation).

5. Using the Integrated Diagnostic System (IDS) scan tool, select DataLogger->Chassis->Braking->Brake Switch Parameters.

6. NOTE: Using the scan tool record function makes it easier to observe the brake pressure sensor readings.

Set the ignition to ON.

7. Slowly apply the brake pedal to generate the pressure graph for the BPS (brake pressure sensor)PID (parameter identification). The rate of brake pedal apply must not exceed 5 psi per second as indicated by the scan tool.

8. Record the initial value of the BPS PID (parameter identification) when BRAKE_LAMP and CRUISE_CANCL change from OFF to ON.

9. If BRAKE_LAMP and CRUISE_CANCL transition to ON before the BPS PID (parameter identification) reads 44 psi or less, the brake pedal position switch is correctly installed.

10. If BRAKE_LAMP and CRUISE_CANCL transition to ON after the BPS PID (parameter identification) reads greater than 44 psi, replace the stoplamp switch and cruise control deactivation switch (if equipped). Clear all Diagnostic Trouble Codes (DTCs) and repeat Steps 3-6 to verify that the BRAKE_LAMP and CRUISE_CANCL transition to ON before the BPSPID (parameter identification) reads 44 psi or less.