Well we just bought the car, and we knew it did this when i bought it (a 96 LS for 2k was hard to find considering thats how much 90' LS's go for around here, and there's not many!) but this is the ONLY problem (aside a few dings I'll have no problem getting out)

We checked the fuses and all the bulbs, the tail light was full of water so we drained it, and dried it, and it still acts the same.. so we think its the wiring and we don't wanna take the whole car apart unless we have to (which we might to get the rear speakers in anyway >_<)