I have a '99 Saturn SC1 that has lost its back window. I did an apparently poor job of putting up plastic, so water got into the trunk. My battery will no longer hold a charge. I have pulled the fuses for the dome light, the door locks and the rear defrost but the battery still drains. I would like to have some idea what the problem is. The window alone will cost me $200+ dollars so I am hesitant to fix it if diagnosing and fixing an electrical problem on my old Saturn will cost the same or more.
Have you pulled the carpet, spare cover and spare and any and all covers and let it dry out? There may be water in the spare. There is alot of tail light and trunk light wires that will need to dry out. Pull the connectors and put dielectric grease on them. This should fix your problem.
Most likely water in the middle brake light. Replace teh back window and the wiring problem may take care of itself. I say may because the battery drain may not have anything to do with the back window.
First things first . . .
Perform a parasitic draw test to determine what circuit is draining the battery. It might not have anything to do with the back window