Brake lights stay on -- not the brake light switch

[davewah3]

This seems to be a popular problem with the Blazer/Jimmy/Sonoma/S10.

It started about a month ago on my 2000 GMC Sonoma. The brake lights would stay on until I would tap the brakes a little and they'd go back off. As of yesterday, a slight tap does not fix the issue and the lights stay on all the time with no keys in the ignition. I took it in for a diagnosis and was suggested to replace the brake light switch. However, I noticed that the light above the rear cab behaved normally -- hinting to me that it's not the brake light switch. Skeptical, however, I replaced it anywas since it was only $8 to do it myself. However the same problem continues to happen.

Another important note is that the turn signals behave normally. If I hit the turn signal, the light for each side kicks into turn signal mode and out of brake light mode. So that tells me that it's an issue somewhere in the wiring between the brake light switch and the turn signal switch. Or at least that seems logical. Any suggestions before I go get raped by a grease monkey?

[blazes9395]

Your right in that these trucks commonly have brake light problems. It usually can be traced back to the multifunction switch . It controls the the brake lights and hazzard lights. It has no effect on the third brake lamp and thats why it is working alright. There was a recall on this problem back a while ago, but its best you check with your dealer with this.

[Rick Norwood]

Multifunction switch is my opinion too. Half the world's electricity passes thru your multifunction switch, well at least most of you truck's electricity, so, they ain't cheap. Get a good diagnosis before replacing it.