Brake Light Switch Adjustment ??

Back the car up to a wall (or have a helper) so that you can see the brake lights. Push the plunger in on the brake light switch to see if it does indeed work to turn off the lights. If it does work next would be adjustment. You want to adjust it so that plunger is pushed in all the way with no pressure on the brake pedal. With the pedal at rest the plunger is in and when you press the pedal the plunger extends outwards causing the lights to illuminate.

The brake lights should come on after the pedal has dropped a slight amount. It is kinda hard to describe the proper amount of pedal travel prior to the lights coming on, but there should a small amount.