GM-GMC: no brake lights on 2008 GMC Sierra, 2008 gmc sierra, gmc sierra

Question
I have a 2008 GMC Sierra Super Crew (2-wheel drive). Recently the rear brake lights and the third light (cab light) quit working when I apply the brakes. Lights are on but no bright red lights display when I apply pressure to the brakes. Only recent maintenance was an oil change at a Valvoline Express where you stay in the vehicle. They had me apply pressure and they said the rear brake lights were working but the third light was not. That was 2 weeks ago. Went in on Friday for a new front tire and alignment and my wife followed me and told me the brake lights were not working. Any ideas?

Thanks!

Answer
i had the same problem! 2005 gmc sierra.. i had to replace both pig tails in the rear because they were blowing my fuses and causing the lights to go off and on ... work sometimes and sometimes not.

i also replaced the main panel the pig tails plug into. which is located behind the rear driver side tire you should see a panel where the brake lights tails and a trailering plug would plug into if you have that. its mounted to the frame.

it took me i dont know how long to figure out that it was the pig tails for the rear brake lights that were causing an issue.

i am not sure about the cab light that i am not sure if it plugs into the same panel or if its separate.

check all the fuses related to the rear lights not just the brake lights.

let me know what you find...

i will tell you the first thing i tried and it worked for a little bit was that light grease that you put on the bulbs to put in the pigtails and for a while it kept them cool enough that they worked and then a week later they failed again