Brake light not working properly

2008 CADILLAC DEVILLE DTS

121,000 MILES

KELLY TRAP5896

MEMBER
1 POST

Brake light wont come on when I turn the lights on.Signal works, back up light works. when I apply the brakes it comes on. What could be the problem?

Aug 5, 2019 at 10:56 PM

STRAILER

✓Experienced Mechanic
55,104 POSTS

Hello,

It sounds like the BCM is going out. To be sure lets check the fuses. Here is a guide to help us with the brake light wiring diagrams below so you can see how the system works and which fuses to check with the BCM location and replacement instructions below:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

A CAN scan would help see if the BCM is bad as well.

https://youtu.be/InIlnsjOVFA

Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.

Images (Click to enlarge)

Professional Diagram for 2CarPros Members
Click here to log in and view diagram.

Aug 7, 2019 at 12:22 PM