Third BRAKE light stopped working

[RST Dana]

Where do you see that? I see two posts by the OP and neither one indicates the results of any testing.

Ok. It wasn’t op. Just another member.
As you were…..

 

[RP_NY]

On my 2003 Denali XL, I noticed that the third break light stopped illuminating when breaks are applied. The normal break lights go on. Is there a fuse or something that controls the third break light? Or is it a single bulb that burned out?

Thanks!

You can dis-assemble the Unit by carefully prying the Red len from the black body of the light. You will most likely find that the (1) 12V/1W Zener Diode on the circuit board needs to be replaced (do to corrosion) ($1 part)

Image below is what it looks like on 1999 K1500 Suburban

 

[jhilario72]

Thanks all. I just ordered one from Amazon for $25 and it worked. Nice bright LEDs