Shawn;

If no one has been in there doing any "creative wiring" it's pretty likely that you're just dealing with poor connections as the other poster mentions...these are a sometimes a pain to find and can give some pretty whacko symtpoms...as you noticed!....I'd start by cleaning all fuses and their contacts, preping with anti-corrosive zinc paste, but install them one at a time and watch for the symptoms as you do...this may help locate the circuits involved...once you narrow it to a circuit, clean and prep all its chassis connections for starters...retest....good hunting!

See: http://www.intelab.com/swem/anti_corrosive_paste.htm

Gently poking around at suspect curcuit components and connectors with an "insulated poking tool" (IPT) might help too...the give-away chopsticks from the last oriental dinner are perfect for this...

Cheers