97 silverado, 145000 mi. auto, 5.7 Vortec won't start

Son’s truck. Periodically over the last 3 years the truck wouldn’t do anything when trying to start (all dead). After checking battery terminals, cables, recharging battery (if needed) would start fine and go for months without problem. Replaced battery about 2 years when problem reoccurred. About a year ago same problem and shop replaced alternator with OEM. Alternator light never came on. Yesterday same problem. Volts on battery 12 and started when I cranked couple hours later but went dead a couple of times immediately. Pumped gas a bit after third start and then ran fine. Today drove a few miles and won’t start. Checked battery and was good. Voltage to fuse block good. Turned key to acc and all dead except hear a faint clicking sound and the light illuminating the transmission gear ondash on. Turn to start and all dead and volts immediately go to zero with meter across engine to top of fuse block. I think this is all part of same intermittent problem. Wondering about starter motor short in certain position or short in ignition wiring. Ideas welcome. Money tight and hate to guess. Sorry for long post but thought history important. Thank you.

By experience I say the original Delco battery leaked acid at the postive terminal and your inspection of the cable was not intensive enough. This leaking acid can “wick” down the cable and destroy the starter solenoid.

I’ll check this tomorrow. Never replaced a starter solenoid but I assume it is mounted on or next to the starter motor and this can cause a short to ground. Any way to check before replacing? The battery still has voltage, it measures 0 when turning the key only. I do hear a rapid clicking sound from under the steering column inside that only stops when I put the key in and turn to the start position. Not enough power left in the battery now except to see the inside lights glow dimly when opening the door. I was going to seeif the head and brake light worked without the key in the ignition to try and further isolate the problem. Afraid to jump start now, might mess up the good vehicle.

The acid makes any bakealite material that the solenoid is made of brittle, at times the entire postive cable terminal (at the solenoid) will break off. You can inspect for this visualy. I am more suspicious of your battery cable, espically at the battery end.