if the clutch is hydraulic operated, bleed the cluth
if it is mechanical cluth, adjust the linkages
Make sure that there is power getting to the ac clutch when the switch is jumped. If the power is there then the clutch is bad and needs to be replaced.
The clutch will have to be replaced. The pressure plate could possibly be resurfaced but usually it is as cost effective to replace the pressure plate.
The pad on the clutch is getting low
Hydraulic clutch on that model is not ajustable. You either have a bad clutch slave cylinder, Or the clutch and pressure plate needs replaced.
because you didn't adjust the pressure plate
Installed incorrectly, driver who rides the clutch, clutch out of adjustment, weak pressure plate, that should have been replaced along with the clutch.
It sounds like you have a worn out clutch disc or the pressure plate is not applying enough pressure to the disc. Either way, it does sound like you are ready for a new clutch.
bad clutch, bad pressure plate, throw out bearing, air in the hydraulic lines...etc
Easy just bolt it to the fly wheel. hey presto new clutch. I suggest getting a manual that shows how to to this ...its not that difficult of a job but does require an alignment tool to correctly align the clutch disc and pressure plate. Tool is inexpensive... You will need to replace the clutch disc,pressure plate,throw out bearing ,check and maybe replace the pilot bearing and either have the flywheel resurfaced or replaced.
Clutch repair for a 1992 Sierra will depend on the problem. Clutch systems consist of the clutch, pressure plate and a master and slave cylinder. These parts are not repairable, and the part that has failed will have to be replaced.
Bad part, improper instillation, abuse by driver............
usually a clutch does not seize. what happens is that your clutch is not moving, it could be from: no fluid in line, broken fork, air in the line, damaged pressure plate. but if for some reason the clutch is seized... then you will have to replaced clutch and flywheel.