The best way to fix the brake light switch is to wire in a modern, normally
on, plunger type brake light switch. This type of switch is very important if
you have cruise control, since it will turn the brake lights on and shut the
control off, as soon as you touch the brake pedal, rather then after the
pressure builds up in the system.
There are many switches available at auto parts stores. I prefer the all
metal ones with more durable mounting threads. Support the switch with a simple
bracket from the under side of the heater box so that it is activated by the
brake pedal arm. The further the contact point is from the arm pivot the better.
Tap one wire into the green and purple wire that goes to the brake lights
under the left side of the dash by substituting the original connector with one
of the standard dual connectors. Connect the other wire to any all green wire
found under the dash. If the original switch is not leaking, it can be left in
as a redundant switch.