Chrysler Repair: Battery Drain, brake light switch, fuse box

Question
The battery on my 1984 Fifth Avenue kept losing it's charge and draining even after recharging and running for a while. After doing some testing and removing the fuse we have narrowed it down to the brake lights/interior lights as when the fuse is removed the battery will maintain it's charge and start up with no problems. Several opinions have been given to me from the brake light switch to the auto switch that turns off the headlights. Not quite sure where to look next, would you have any ideas/suggestions?
Thanks for your time.

Answer
Hi Bob,
I trust that the fuse isn't blowing so we aren't dealing with a short circuit to ground. Fuse #6 is a 20 amp according to the '83 diagrams I have. So if that is the one that when removed ends the problem I would try to find any lights that are staying on all the time. The interior lights are all visible EXCEPT the glove box light and the trunk light. So try verifying that both of those are off when their respective doors are closed. The trunk light is based on gavity (tilt) so that one may be stuck closed. If you trust your significant other get in the trunk and have her close the lid on you. The other thing that might be stuck on is the cigar lighter, or there might be a partial short to ground at the socket. What you could do to verify those three items is to measure the resistance, from the 'cold' side of the fuse socket (the one that doesn't have 12V on it until you of course insert the fuse) with the fuse removed, to ground (any shiney metal surface). Then remove the glove box bulb, the trunk bulb, and unplug the lighter's wire connector, one at a time, to see which one causes the resistance to jump up. Of course you have to have all the doors closed when you measure this so as not to add all those interior lights to the circuit if you are going to find which one is staying on. The key lamp may be stuck on too, so take a look at that at night. Finally the headlamp on/key-buzzer/seat belt warning module in the fuse box (left side) may be defective so try unplugging that too and see if the resistance reading rises.
Those are my ideas for now. Let me know if you find out.
Roland