kz 1000p brake issue

Working on my 88 kz1000p and the I can not figure out why I do not have any brake lights. key on I have a tail light on, cleaned the switches and I have good continuity on the switches but no lights when I depress either pedal/handle. There are three wires going to the tail lamp black/yellow, red and blue. Black/yellow is ground red is the tail lamp and the blue is for the brake lamp. on the brake switches the wires are brown and blue and the brown run all over the place. Tried to short the brown to ground at the switch and blew a fuse, Yah yah my bad. dont really know where to start to trouble shoot from here, any help / input would be great thanks in advance
also looking to remove all the police stuff but I have not removed anything as of yet

You didn't mention checking the light bulb filaments

First at all,never shortcut any wiring if you don´t know how it work correctly whithout a wiring diagram.
Use a Multi meter to test and follow the voltage/current flow to/from the break switch to the break light bulb .
BTW, you have to shorten the brown/blue wire to Bypass the brake light switch.

Bulb checks out good on both filaments

yep did all that by passed both the front and back switch one at a time

If not already done, would check switches with ohmmeter or bulb to assure current pass through when the switch is activated.
I believe the front brake switch is a pressure switch and that the rear brake switch is a mechanical version.
If the switch functions correctly (allows battery+ current to pass through the switch when the switch is activated), and the brake bulb still fails to light up, I would suspect either a break in the battery+ wire from the switch to the rear brake bulb filament, or a defective ground for the brake bulb, or a defective or loose brake filament in the rear bulb.

Would also double-check the rear bulb brake filament by removing the bulb and using test wire to connect it directly to the battery posts.

Good Fortune!