I have a 99 Blazer. The reverse lights started blowing a fuse. Funny thing is, that if I held the right rear window switch down they worked for a bit. I can't figure out what's going on here. Any help would be appreciated.

 

I would see if the Neutral Safety switch off the side of the transmission and see if it is bad. I think your 1999 will be similar to my 1997, my reverse lights weren't working and I replaced the switch and they work to this day.