I've seen two taillight problems posted in the past day. Well, maybe for one or another, this might help. There are several problem areas (bulb holders, worn circuit board, the connector and even the "bulb out" module) -- here's my recent experience with one such "fix".

I had a chronic, intermittant bulb failure -- every few weeks, and then merely days, during the past winter, my driver's side (naturally, the side for which I have to pull out the spare tire to work on) taillights would stop working. It wasn't the bulbs -- I changed them (in pairs, no less) to no avail! I would wiggle the sockets, and they would come on -- and then a few nights later, they would go out again.

Naturally, I first blamed the circuit board and/or the bulb holders' contacts! But I cleaned them up with electrical circuit board cleaners, and yet the problem persisted.

Finally, I found the problem -- it was the electrical connector (white, rectangular) that fits onto the folded piece of circuit board. Its clamps just weren't tight enough anymore. At first, it wasn't clear, but by this end of the winter, I saw that just wiggling it would turn off or on the taillights (note, the problem only affected the taillights, not the turn, brake or reverse lights, so only one of the contacts inside the connector was bad). I had cleaned up the contacts and the circuit board underneath when I cleaned up the bulb holders' areas earlier.

I tried bending the contacts tighter -- no improvement.

Finally, I took little strips of thin conductive foil, folded in a U, and placed them (using fine dissecting forceps -- "tweezers") inside the connector (just under each contact) so that they lay between the circuit board (both sides) and the contacts to make a tighter union.

Haven't had a problem for over a month.

So when you're having taillight problems, consider the connector too. It isn't always the bulb holders or circuit board.