Tail light not working properly

[Twoney_Money]

Hello, my neighbor is needing help with his 2015 EcoBoost mustang. The driver's side tail light far left strip is always on. When he presses the brakes, the far left is on, but when he lets off the brakes, the left one continues to stay on. The same for the turn signals, the right one operates properly, but the left one sequences, however, the left one still stays on. The dashboard does not blink faster or slower so I don't think it is trying to give a code like other posts were saying. He did buy this used, so he is unaware of if it was tampered with, but from the looks, it seems to be stock. Does anyone have any similar experiences or know how to fix it? I am thinking it may be just needing an ECU flash, but they are so expensive and I don't want him to have to pay for one and it still doesn't work. Any help is greatly appreciated. thank you!

Here is a video of the tail light sequences:

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[Cobra Jet]

Here ya go - go to this thread, then to Post #25:

https://www.mustang6g.com/forums/threads/tail-light-out-then-back-on.101551/page-2


There’s a lot of info in that thread too about various taillight issues.

 

[Twoney_Money]

Here ya go - go to this thread, then to Post #25:

https://www.mustang6g.com/forums/threads/tail-light-out-then-back-on.101551/page-2


There’s a lot of info in that thread too about various taillight issues.

I read this but this talks about it not working. for my case, it just doesn't turn off :/ i don't know why it doesn't function properly

 

[Rob_GT]

I read this but this talks about it not working. for my case, it just doesn't turn off :/ i don't know why it doesn't function properly

I know it's been awhile but did you fix the issue. I came across the same problem with my 2016 GT.
Cheers!

 

[Skye]

While I do hope you receive some feedback, the OP has not accessed their account since 2021.

 

[Twoney_Money]

I know it's been awhile but did you fix the issue. I came across the same problem with my 2016 GT.
Cheers!

Hi, I ended up taking it to the dealer and I believe he ended up clearing something and it worked. Sorry, this was a while ago so I do not have that much information.

 

[Rob_GT]

Hi, I ended up taking it to the dealer and I believe he ended up clearing something and it worked. Sorry, this was a while ago so I do not have that much information.

Thank you very much! I really appreciate the answer. Have a nice weekend!

I guess I'll go find a used OEM replacement.

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