Please Help! Third brake light problem
 

Hi All-

I have a r129 500SL that has an interesting problem; while the rear brake lights function correctly, the entire third brake light bar does not illuminate. The bulbs appear intact.

Any thoughts or suggestions?

Scott

Sure, this is a super-common problem on 129's. The power or ground wire (or both) crack and open in the area of the hinge. It's on the right side hinge bar. You need to take the plastic trim off of that hing and expose the wiring in that area, you'll find it. Need to solder in some new wiring is all.
It doesn't indicate the fault on your bulb failure system because the center stop lamp is direct from the brake switch, doesn't come through the exterior lamp monitor control unit.
Gilly

Thanks Gilly-

I tried your recommendation without luck. Anyone have any other thoughts/ideas?

Scott

WE(dealer) always fabricate a new section of harness from the rt side of the fuel tank & run it into the deck lid as many times the wiring where the hinge pivots is stretched & a quick repair won't hold long.
YOU need to get into the harness beside the fuel tank.