HELP!! My car is having an electrical problem!?

Okay, I have a 2004 Chevy Impala Standard (3.4L V6). I was currently on Active Duty and left my car with a family member. My car hasn't really been driven much BUT by it sitting there for 9 months, I noticed a problem. Where I'm from, we have bad winters and by my car sitting outside in the snow, it melted and the water somehow is flowing in my tail light panel [..and I drained it out]. After awhile, I started to notice that when I use my keyless remote [to unlock my doors] or reverse, my clear lights doesn't illuminate AND my horn doesn't work either! My brake lights, headlights, blinkers, hazards,cigarette lighter, and wipers work normal. Otherwise, is this a fuse problem? If so, please explain. If not, still please tell what may be going on with my car. I'm taking it to the shop in a couple of days but I kind of want to troubleshoot first or play with the fuse box before I spent a lot of money. Serious answers please...