Brake Warning Light and Parking Brake Set Warning

[dhammy25]

We have a 2008 Expedition and when starting the truck the Brake Warning Light stays on or flashes on and off intermittently. When you start to drive the center display starts saying parking brake set and starts chiming. Below are the steps I have done thus far and the results

1. Checked and added brake fluid, no change
2. Disconnected the sensor on the master cylinder, no change.
3. Jumpered the two outer wires on the master cylinder sensor connector and got a brake fluid low warning.
4. Disconnected the parking brake sensor, no change.
5. Replaced the parking brake sensor, no change.
6. Ran an OBDII scan using Forscan Lite and there were no codes related to the braking system.

There are times when everything works normal and I can engage and disengage the parking brake and the light comes on and off like it is supposed to. Then out of know where the light will come on and stay on. There have also been instances where the light was off and the second I shut the drivers side door the light comes on.

The two links listed below are the closest that I can find to my problem, but it doesn't look like either one was resolved.

https://www.justanswer.com/ford/5i515-ford-expedition-4x2-2008-expedition-brake-light.html

https://www.justanswer.com/ford/7rua4-ford-2010-ford-f150-brake-light-on.html?fbclid=IwAR0MvKEPOeozDgMC8nyWFCD0jbaxoUhBJFhlndCc7CeuHyoZM3GXRTT7z5o

Has anyone had this problem and been able to fix it.

 

[rwmorrisonjr]

Did you check the rubber stop on the top of the brake pedal lever that pushes on the indicator switch? It sometimes gets pushed sideways and causes the issues you're experiencing. I finally drilled a hole through mine and bolted it down so it wouldn't keep shifting and that fixed the problems.

 

[dhammy25]

Yes, the rubber stop is there and works. When I do most of my testing I'm activating the sensor by hand.

 

[dhammy25]

Just to follow up on this to close it out, the problem ended up being a shorted out Smart Junction Box (SJB). Not 100% sure, but we added a dash cam to the truck and it could have shorted it out when wiring in the power.

 

[Motorcity muscle]

Great job on follow up and your post will help others.