intermittant 3rd brake light?
 

on my 05 boxster, recently my 3rd brake light has been intermittent. I have removed it and found it is a non serviceable led bar. it appears the connection to the light bar is in good working condition (no corrosion or frayed wires). the rear lower brake lights are functioning properly. but the warning message keeps appearing on my dash display for the onboard computer. while stuck in traffic, I noticed the third brake light going on and off in the rearview mirror from a reflection in the bumper of a truck behind me. so I have a confirmation this is a light problem and not a computer glitch. I was wondering if someone has had a similar problem and what their solution was. I don't think it is the brake switch, because the brake lights in the tail light assemblies are not intermittent. any ideas, or is this a replace the 3rd brake light bar?

thanks in advance for any suggestions

I would get a live feed from the good working (lower) brakelights and feed it to the 3rd light, see if that works if no, get a new earth to the 3rd light and take it from there if it works cut and isolate the us wirers.
Guvs.

I just replaced the light with a used one purchased from the e- place. seems to be working properly now. will be keeping my fingers crossed for now hoping this was the remedy. I just hate being a parts changer and hoping it works.