Hi any Brake guru can help?

2006 X5 M54 138K with RED Brake Light...

Not the famous Trifecta, but ONLY one RED light is on as shown.
I have INPA, but I don't know which section of INPA to open to look.
Hopefully this is not the DSC Module.

- How do you approach the RED Brake light?
- What software, what trick?
- What is the usual culprit?

Thanks...

Attached Images

 

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1998 E39 528i 5sp MT
2006 E53 X5 3.0 6sp MT