(tip) Brake lights inop, blown fuse

[fetchthecomfychair]

I have seen this a few times years ago in the dealership and now on my own truck. There's no service bulletin about it.

If you have a brake lamp fuse that blows (either intermittent or constant), and your truck has adjustable pedals, most likely the cause is a damaged harness at the brake switch where it loops up over the steering shaft. The factory routing of this harness is not very good. Note the telltale rust caused by arcing.

If the wire(s) are still intact, just wrap with tape and add some sturdy split loom for protection. No need to cut and splice if it's only insulation damage. Also add a piece of loom over the edge of the bracket.

Note in the underhood fuse box photo, the only aftermarket fuse is #12 Stop Lamps (circled). Obviously this was a problem for the previous owner too.

 

[Reprise]

Good stuff, and welcome aboard!
I always like when a GM tech joins the forum, as there's much 'inside info' that gets shared - just like with this item.

 

[Mooseman]

Very nice. Added to FAQ.

 

[Reprise]

Also kind of curious to know what drove the OP to choose an Envoy over, say, a Sierra or Yukon. (a new thread in 'Member Intros' is good for this)
(And there's no shame in saying "b/c it was cheap, compared to the others")

 

[fetchthecomfychair]

It was beyond cheap. No joke, it was on fleabay for $2395 buy-it-now. Georgia salvage title because of a minor hit to the right lower bumper (no body damage other than the bumper cover). I wasn't even looking for a 'new' truck.

 

[Reprise]

Kinda surprised it got a salvage title issued just b/c of that. Worked out good for you, though!

 

[fetchthecomfychair]

More info...

There are 7 wires at the brake switch connector, so a chafed harness at this location could affect other things besides the #12 fuse and give different symptoms. For instance if the pink wire goes to GND it kills the IGN 1 ckt (I think the IGN E fuse, #22, and possibly others that feed it - the diagrams are... difficult to use in this way ("Hrm, wonder what would happen if...")).