Brake lights are stuck on with headlights on

[tfach]

Hey everyone this is my first post, I’ve been researching for a couple months now scrolling through this forum to see if anyone has had the same issues or not and the only one that’s come close was with a modification done to a high level brake light on another members post back in 2018 I believe….So my 2014 explorer XLT has recently decided to start giving me some issues. Mechanically it’s a smooth running rig. Heres my issue, without my running lights/headlights being turned on manually/auto, my brake lights function as they should. When my running lights/headlights are on the brake light brightness is activated including the high level brake light there’s no difference in light output when my brake pedal is pressed making it look as though I’m driving down the road constantly braking. I’ve replaced the stop light switch twice thinking maybe I got a skunk part the first time to realize that didn’t change anything. I’ve taken the brake light housings off and looked over wiring with no indications of a pinched wire or bare wire anywhere. No moisture is in either of the assemblies and no modifications have been done. I’ve had this explorer since 2017 and it just started doing this. It is random at times and I’ve noticed when it rains or I wash my rig it’s more prone to happen but corrects itself after a few days of possibly drying out???Any help or advice would be greatly appreciated.

 

[jmr061]

Sounds like water in a connector or taillight that is shorting the running lights to the brake lights. When it is doing it, pull one rear lamp assembly at a time and see if removing one eliminates the issue for the other one.

 

[tfach]

Sounds like water in a connector or taillight that is shorting the running lights to the brake lights. When it is doing it, pull one rear lamp assembly at a time and see if removing one eliminates the issue for the other one.

Up to this point I have not noticed any water or condensation build up in any tail light assembly. But I will give that a shot. Thank you!

 

[Johny H]

Hey everyone this is my first post, I’ve been researching for a couple months now scrolling through this forum to see if anyone has had the same issues or not and the only one that’s come close was with a modification done to a high level brake light on another members post back in 2018 I believe….So my 2014 explorer XLT has recently decided to start giving me some issues. Mechanically it’s a smooth running rig. Heres my issue, without my running lights/headlights being turned on manually/auto, my brake lights function as they should. When my running lights/headlights are on the brake light brightness is activated including the high level brake light there’s no difference in light output when my brake pedal is pressed making it look as though I’m driving down the road constantly braking. I’ve replaced the stop light switch twice thinking maybe I got a skunk part the first time to realize that didn’t change anything. I’ve taken the brake light housings off and looked over wiring with no indications of a pinched wire or bare wire anywhere. No moisture is in either of the assemblies and no modifications have been done. I’ve had this explorer since 2017 and it just started doing this. It is random at times and I’ve noticed when it rains or I wash my rig it’s more prone to happen but corrects itself after a few days of possibly drying out???Any help or advice would be greatly appreciated.

Check both bulbs.. sometimes if one burns out the filament will short to the running light

 

[tfach]

Check both bulbs.. sometimes if one burns out the filament will short to the running light

It’s a 2014 the brake lights are LED.

 

[ProjectSHO89]

Water infiltration into one of the tail light assemblies is the most likely problem.

Yes, the lights are LEDs so that eliminates the filament theory. However, an intermittent short between circuits at or in one of the assemblies would be high on the suspect list.

If a visual examination of the assemblies isn't revealing, it's time to get creative.

1. Catch the system malfunctioning.
2. Unplug each of the tail light assemblies, one at a time, and see if the high-mount stop lamp goes out when it was previously on.

 

[tfach]

Water infiltration into one of the tail light assemblies is the most likely problem.

Yes, the lights are LEDs so that eliminates the filament theory. However, an intermittent short between circuits at or in one of the assemblies would be high on the suspect list.

If a visual examination of the assemblies isn't revealing, it's time to get creative.

1. Catch the system malfunctioning.
2. Unplug each of the tail light assemblies, one at a time, and see if the high-mount stop lamp goes out when it was previously on.

Thank you!! I’ll give it a try. They have been on now for about 4 days in a row which is the longest that I’ve seen this issue. I’m hoping it’s just as simple as replacing a tail light assembly ya know

 

[peterk9]

Thank you!! I’ll give it a try. They have been on now for about 4 days in a row which is the longest that I’ve seen this issue. I’m hoping it’s just as simple as replacing a tail light assembly ya know

Welcome to the Forum.
Good luck and please do update. Thanks.

Peter

 

[tfach]

So update, today on shift at the FD I had a free moment to dig into this issue a little bit. I’ve tried disconnecting one tail light assembly at a time to see if it changed anything and unfortunately it did not. I pulled the inner panel off of the lift gate as well to check all wires and connectors coming from the high level brake light with no difference either. No indications of water coming in and no exposed wires. Since I’ve eliminated the theory of water in the tail light assemblies and high level brake light could there possibly be water getting into the fuse panel up under the steering wheel close to the firewall creating a short between the headlights and brake light relays? I’m at a loss right now.

 

[steveatthebeach]

It’s a 2014 the brake lights are LED.

I’d be willing to bet that therein “LED” lies your problem.

 

[tfach]

UPDATE UPDATE UPDATE!!!

I took it to a local shop that specializes in being electrical wizards and have found the issue. I had a bad connector. New harness in and everything works as it should.

Almost $400 for diagnostic testing parts and labor.

Ford Part number: BB5Z13410B.

 

[peterk9]

Thanks for reporting back. Perhaps it may help others down the road.

Peter

 

[jmr061]

A 45 dollar part and $400 bill. That’s crazy.