Ok here's the deal...

3rd brake light gradually (quickly) loses power until its hardly visable.

other brake lights work fine

bulbs in third brake light are good (I checked them with a different power source)

The ground is good on the wire for the 3rd brake light, so its a problem on the power side.

fuse is good in side panel fuse box

Anyone have any idea's what it could be?

Thanks,
Archie

 

there is a spot in the power wire to the light that has high resistance, inspect the wire in the area in goes into the hatch, probably in the top area, near the hinges

 

I'll check that out.

Thanks