I have a 92 Blazer, and the charging system is causing problems. First, the plug on the top of the alternator is broken. None of the wires on the plug are hooked up. It may be a 4 wire plug alternator, but I don't know. It seems the male part of the plug (inside the alternator) is broken.

Additionally, every fuse in the fuse box is powered when the ignition switch is on the off position. If I remove the postive cable from the battery over night, the truck will start every time. If I fail to unhook the positive post from the battery, the truck will not start. When the truck fails to start, I usually get a jump. Strangely enough the jump is really fast. As soon as I put the cables on the battery, the truck will immediately start.

If you have the free time to lend some insight into the wiring, it will be much appreciated.

 

The alt should only have 2 wires on the plug (gray and pink I wanna say)
As for power all the time, I would replace the ignition switch and see if that fixes your problem. They can cause weird things.