Our posts have overlapped somewhat!

From what you say, I am now pretty sure you'd connected the blue/black parking light wire (on the bike's loom) to the brake light circuit on your new LED lamp unit. Which is why the LED unit was at its brightest all the time and the brake switches made no difference (as they would be connected to the low power LED tail light circuit in the LED unit).

Then I guess you tried to rectify it and connected one of the live wires (either yellow or blue/red) to the LED unit's earth wire and caused a short, probably because the earth on the LED unit is also grounded through the tail tidy mounting bolts to the frame(?) So..

(1) Disconnect the LED lamp unit completely.

(2) Check your fuses (replace if necessary).

(3) Charge the battery.

(4) Try starting the bike (hopefully it will).

(5) Establish which wire (blue, yellow and green) is which on the new LED lamp unit by connect to a battery (or use a multimeter). MOST IMPORTANTLY WHICH IS THE EARTH/GROUND.

(6) Reconnect LED lamp unit now you know the correct colour codes of the wires and it's polarity (LEDs will only work with current flowing one way, unlike normal filament bulbs).

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