GMC 2003 Envoy third brake light delayed

I noticed something odd today when I was driving behind my husband. He was driving our 2003 GMC Envoy and when he applied the brakes both tail light brakes lite up right away but the third brake light was delayed. I would say it took about 6 or 7 seconds before it came on. Why would it be doing that? I think it should light up immediately with the other two lights.



Any idea of what could be wrong? Oddly enough, we just had it inspected that day so if it’s something that should have been caught it wasn’t.



Thanks for any suggestions.

Poor ground in socket(s) or possible faulty wire between the hatch and the body (from opening and closing the hatch).

Perhaps just a bad bulb filament.

Could be a fault in the power wire that comes from the stop lamp switch up front.

I think your Envoy and my Tahoe have pretty much the same wiring system.

I just double checked my Tahoes’ high center brake light. It is independent of the hatch. Being as such, there is no broken wires due to opening and closing of the hatch.