Hi and welcome to NICO Club!
What switch, the one under the pedal? There is a 2 amp fuse between the switch and the computer (maybe close to the switch?), maybe you blew that while working by not unplugging your battery first? You can look into the brake light system with the Factory Service Manual (FSM). Here's a link to the FSM chapters (it was broken down to smaller files). There is a FWD forward chapter with table of contents and somewhere in there is a decoder for wire colors used in the schematics, the BR chapter with brake system information and the EL chapter with electric stuff (look at EL-73).
http://www.nicoclub.com/FSM/Maxima/2002/