Solved - Tail lights stay on and/or difficulty shifting out of park, bad brake sensor | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Solved Tail lights stay on and/or difficulty shifting out of park, bad brake sensor

Prefix for threads that contain problems that have been resolved, and there is an answer within the thread.


New Member
September 25, 2008
Reaction score
City, State
Year, Model & Trim Level
03 XLS
Just wanted to post this for anyone facing this same issue. My 2003 Ford Explorer 4x4 (4dr XLS non-sport trac model) recently started leaving the tail lights on even when parked and shut off. This was causing battery drain and the tail lamps were physically hot to the touch. The previous day I had difficulty shifting out of park and had to rotate the steering wheel and reinsert the key a couple of times. Both of these symptoms coincide with a failed or failing parking brake sensor. If you follow the brake pedal up under the dash you will see a green locking pin. Pull the pin out with needle nose plyers. The sensor can now slide off the stud holding it to the brake pedal arm. Pinch the tab on the wiring harness to unplug the sensor switch. Make a note of the numbers on the part. If the black bushing falls out, make sure to save it. My sensor was black with a gray plastic cover plate. It is Motorcraft SW6218 Brake Light Switch available on Amazon for about $16. Note that Amazon indicated the wrong sensor (possibly confusing the car with the Sporttrac model) for my car so it's important to pull the part to confirm.

I had tried pulling various fuses from the panel and could not get the tail lights to shut off until I removed the sensor. Since the part takes several days to order, I decided to attempt to repair the broken sensor. I was able to use a pick to remove the gray cover to expose the switch. It has a black plastic push button that slides to drive the pins together when the brake pedal is pushed. One of my pins was fused to the plastic plunger from heat, most likely caused by resistance from dirty contacts. The pins can be pried up for cleaning. Once I pried them up and separated the pin which had fused to the plunger, the mechanism was able to function again leaving the contact open with no pressure on the button and closed with pressure on the pedal. To test, push on the plastic button to make sure it compresses against the spring and moves freely. Lube it with silicone spray. Polish the contacts on the metal pins and clean them with parts cleaner or electronic contact cleaner. After reassembly the part functioned normally but I will still replace it for peace of mind.

The purpose of this sensor is to control a shifter lockout solenoid to prevent the car from being shifted out of park when the driver's foot is not on the brake pedal. When the sensor fails in the circuit closed position, you will have your tail lights stay on indefinitely. When it fails in the open position, the shifter will not move out of park. If you are stuck in park there's a slot on the underside of the steering column where you can insert a flat blade screwdriver to manually release the shifter lockout. Other causes of the car failing to shift out of park can be a failed shift brake lock solenoid, brake light fuse, brake light bulbs. It's amazing that a $16 part can leave you stranded by either running down your battery or preventing the car from being shifted out of park!


Thanks for the writeup. I set you up with an Elite membership for your contribution.