i have a 1991 Honda accord in which i am having trouble with.the thing is my brake lights!!when i engage my brake pedal only the left side brake light brighten not my right.i replaced my bulbs etc.etc. and to no avail.i am getting power to that particular socket i know cause it uses a dual filament bulb and one of the filaments is working but not the other. help!!!!!!!!!

 

The power comes to 2 different contacts for the 2 different filaments in the bulb, a test light stabbed into the contact in the bottom of the socket might help you correctly and accurately diagnose the problem.
While you are there look at the contact in the bottom of the socket, they are just solder blobs and sometimes wear flat.