1997 Chevy Blazer Blowing fuses

As far as the fuses blowing, the lower brake lites and turn signals use the same circuit, not at the same time.
That circuit is wired through the turn signal switch. The high-mount brake lite is wired a little different. You might check the bulb sockets and wiring.

If you can find the rear connector for the wiring harness for the brake-lite and turn signals, disconnect it, see if the fuse still blows, if it doesn't, the problem should be between the connector and one of the bulb sockets.