I have a 2001 Jimmy SLT, 4 door. Visit a friend the other day, his driveway is steep. Stepped on parking brake, it went right to the floor with very little resistance and no "ratcheting" feel/sound. Putting it in park held, and guitars were played. On the weekend i had a chance to try and find the problem but couldn't figure it out. I did discover that the parking break engaged as long as my foot was pressing down on the pedal, but as soon as i lifted it released. So i'm assuming it's just something in the pedal assembly, what should i be looking for?

 

There should be a ratchet mechanism in the pedal. Perhaps there is a spring for the pawl that broke? If you are lucky it just needs some WD-40.

 

I actually have the exact same issue on my 2002 Blazer. I'll check it out soon and report back with anything useful. Hopefully, you can do the same.

 

I had a problem with my pedal not "locking" when pushed down. Ended up being the "key" that holds the gear in place to lock the pedal, was worn. Bought a new one off Amazon for 20ish$, slight adjustment to the rear shoes, all has been well since... been about 2 years or so now.