XJSETH

ok so my friend just bought a 98 5.9 gc. and when we hooked up the battery to drive it to my house to work on it the brake lights were on the whole time so pulled it into the garage and realized if you pull the pedal towards you the lights go off, you let it free fall the lights come on? weird. so how do we adjust the pedal.

RRAM

well unless the brakes are really worn out and your low on fluid, then most times you would adjust the switch. Back in the day they had 2 nuts so you could move them in and out, not sure how these things are. Could be just bending the bracket will fix the problem.
Now to me it sounds more like maybe this vehicle needs a really good looking at, take all the wheels off check brakes and check fluid, maybe bleed the system, I would say bleed the system for sure.

So in all that I say fixing the switch is easy. But that may not be fixing the problem as to why its doing that.