At one point there was a factory recall on Chevy tailgate cables. Odds are that you've had them replaced at least once. Unlike other truck models that use cables, Chevy decided to rivet one end of their original equipment tailgates cables. The good news is they didn't do it for too many years.
Lower the tailgate.
Lift the tailgate slightly to take tension off either cable that might not be broken. Push the release tab of the upper ringlet to slide of off the striker bolt. Remove the top part of the broken cable in the same manner.
Drill out the bottom rivet (latch assembly hole) of the tailgate cables with a hand drill and a 3/8-inch high speed drill bit. Ream the latch assembly hole with the drill.
Remove the latch assembly fastener from the latch assembly.
Loosen the latch assembly fastener with appropriate sized hand wrench, but not all the way. Do not remove it.
Apply a coat of rust-penetrating lubricant to the drilled out area of the latch assembly hole.
Insert the new fastener and new cable to the latch assembly and then tighten with hand wrench.
Tighten the fastener, but do not over-tighten and strip it out.
Lift the tailgate up slightly again and attach the other end of the cable to the striker bolt.
Perform the same procedure on the other side.
Close the tailgate.
