Brake pedal adjustment

[vectorit]

Been working on my brake lights, and after adjusting the depth of the switch contact point today - engine off, brake lights working when pressing the pedal.

Go for a drive, pull into the garage and notice the brake lights are constantly on even after I turn the engine off.

After looking at the switch, and seeing that it hasn't readjusted itself I just so happen to lift on the brake pedal. It came up about an inch or so, looked over at the wall and see that there is no red light reflection...

So, this is what I figured so far.

Engine off - pressing the brake pedal just as one would be by applying the brakes, the brake lights go off and on as they should.

Engine on - pressing the brake pedal just as one would be by applying the brakes, the lights go on but stay on after pressure to the pedal has been removed.

Simple question I guess... Am I to adjust the brake switch while the engine is running, or does the brake pedal have to much slack in it for the spring to pull it back up?

If the pedal has to much slack in it, what is the rule of thumb to adjusting the pedal?

I've been looking through my documentation, and there is nothing specifically noted about what I am asking above in the books I have.

Thoughts?