1997 Nissan Altima brake light on one side not working

The lights are dimmer on the right rear than those on the left rear. They get dimmer when I step on the brake. Turn signal and back-up light are fine - on both sides as is the middle higher brake light. Just replaced the bulbs - because that is my level of problem solving. The is rain water leaking into the trunk on the right side also.

updated 2-11-09
Well,
I did not have the means to do anything but visually look at the wiring - and all looked fine so I took it to a repair shop which is highly thought of in my town. They said a wire was bad and fixed it. Guess I need to get a gauge of some sort to check these things and some tools do this work myself next time.