This response was posted a couple of days earlier in response to another Brickboarder's brake light problem:

I had a similar intermittent problem with the brake lamps on my '87 wagon. After tweaking terminals to improve contact, it worked for several months, only to have both brake lamps not work at all!

The problem turned out to be deformation of the lamp housing that accepts the lamp-in-holder assembly. With several hour-long waits at the Tijuana border in recent years, the heat from the incandescent bulbs must have easily softened the plastic, allowing the terminals to recede.

I decided that the only long-term solution was to eliminate the heat source. I got two LED replacement lamps from LED Tronics -- not cheap at $25 ea. They run dead cool, are as bright as the incandescents, and will likely never need replacing. It was necessary to carefully bend the receded terminials back up to their original height to restore good contact with the terminals on the holder.

So do a careful inspecton of the terminals to see if they are still all on the same level.