Wiring troubles ????

The fuse box has 2 feed wires on 2 separate bars, one hot at all times and one hot at switch on. What you did was supply the switch on bar with the hot at all times power at the brake light switch though the turn signal switch and flasher circuit. The run the wipers or heater blower this way should over heat some wires / connections / switches.
You're right, this can easily fry something. I only did it for a few seconds. Don't try this at home.