Parking Brake

[Skeld]

At one point I activated the parking brake, and something definitely snapped and I could see the cable had some slack in it where it runs down the frame and is visible from the driver's side.  A bit later I had my shop "fix" the parking brake.  At that point the cable looked good and the pedal seemed to work normally, but I don't know that I ever really tested it.  Fast forward a few years and the pedal still seems to work but it definitely has zero effect on actually holding the truck in place.  Is there an adjustment or is this a deeper issue possibly?