After removing and replacing hydraboost unit the brake pedal dont make contact with the brake light switch. what could be the problem
the brakes are holding slightly without pressing the pedal.
This on my 97 3500

 

I just changed mine and it went so well I thought I was dreaming
Is the replacement new or used? The rod is not in a bind is it?

 

More than likely in the removal you pushed in the pintle on the switch. Remove the switch and pull the pintle back out and push the pedal down and install it back into the bracket. Let the pedal rise and it will "adjust". Worst comes to worst you'll need a new switch....and good new...they're CHEAP!!