Weird electrical problem,,, (aren't they all?)
 

When I step on the brakes, my entire left side taillight goes out (no lights lit at all), but when I'm not touching the brakes the rear taillights are all lit. What the heck is this? Thanks!

If this helps at all, I just replaced all of the talilight bulbs, turn signal relay and several fuses.

electric problem
 

check your ground wire and clean it. poor ground does stop electricity from passing through to bulbs.

Fritz

Out of all the bulbs you replaced -

Pull one bulb - test everything to see if it's normal. If no change, replace the bulb and pull the next one - one at a time.

I have a feeling something is cockeyed in one of the sockets - the tail light and brake circut are seperate. when you're hitting the brakes you're losing your ground somewhere -

rjp

Fritz and Randy,

Thanks, I'll take a look at it tonight!

It seems my taillights have a mind of their own. Sometimes they work properly, but most of the time one or more lights don't work (all bulbs have been replaced) and when the brakes are applied, all of the rear taillights on one side go out. The backup lights oly work on one side. The problem is that when i try to troubleshoot, the lights all work properly, then when I'm driving anywhere, the taillights will invariably fail intermittently. I realize this is a short of some kind, but how do I figure out where the short is?

I decided to remove the taillight assemblies and inspect them and I found the problem(s). The connectors behind the bulbs that attach to the wires were not connected to the taillight assembly. I clipped them back in, cleaned and lubed the connections and tested again and the lights work! All this time, I've been replacing bulbs and fuses, but the latest symptoms indicated a short or electrical connection issue and that's exactly what it was.