Brake light wiring diagrams please?

BILLY2002

MEMBER
2002 GMC SIERRA
5.3L
V8
2WD
AUTOMATIC
140,830 MILES

I replace heater core by R and R the dash, now I found that brake lights don't work, I found no power to brake switch then I chase the harness found other end of brake switch connector hanging, it wasn't hook on anywhere. Please help me out, I been looking for 3 days already still can't find place to plug in. Note: The harness has 4 or 5 wires in it, and about 3 feet long one end connector go to the brake switch and the other end connector go to somewhere. Thank you very much.

3 Replies

DANNY L

MECHANIC
5,648 POSTS

Hello, I'm Danny.

Here is the diagram you requested. I hope the diagram helps to show you where the connector will plug in to. Here is a tutorial showing how to test electrical wiring:

https://www.2carpros.com/articles/how-to-check-wiring

I've attached the brake system wiring diagram below for your truck. I've cut the picture in half so you can view larger. Hope this helps and thanks for using 2CarPros.

Images (Click to make bigger)

SPONSORED LINKS

Was this

answer

helpful?

Yes

No

-1

Thursday, February 4th, 2021 AT 3:04 AM

2CP-ARCHIVES

MEMBER
4,542 POSTS
1999 GMC SIERRA
200,000 MILES

Can you show me brake light wiring harness diagram for a 1999 GMC k1500 4 wheel drive 5.7

Was this

answer

helpful?

Yes

No

Friday, February 5th, 2021 AT 8:28 AM (Merged)

HMAC300

MECHANIC
48,601 POSTS

This is about the best I can do as they are really small. The white wires are power going to t/s switch and overhead cab brake light then it's yellow and green for tailgihts from t/s switch. Also check at rear of frame for ground for all lights they get rusty, dirty and loose contact. Try that first. Also ther eis a circuit board that goes bad in tailights that is available at auto parts

Image (Click to make bigger)