Truck Repair: 1995 Chevy 4x4 Turbo Diesel, chevy 4x4, starter solenoid

Question
Hello, stumped, i have 1995 chevy 4x4 turbo diesel 6.5l  the truck was running and started fine. one day ,it started was turned off, when try to start,nothing happened. not even sound of trying to turn over,just clicking noise.tryed to jump start with another vehicle,nothing. the batterys are approx. 1 yr or so, statered was replaced 5-6 months ago. the battery connections are fine and tight. the starter connections are fine. the engine fuses where ok also. tryed charging both batterys for two hours each one. nothing. the lights gauges and everything works,but still clicking. Can you suggest what to look for.
thanks

Answer
Hello Athena,
I would be measuring voltage at the starter solenoid. First the battery post voltage, then the small ignition switch terminal.
I would probably jump across those terminals, but it is important to make sure the vehicle is in neutral when doing that, since you are bypassing all the safety switches.

If you have good battery voltage at those terminals, then the starter and/or solenoid is probably the problem.

If it will crank over when bypassing there, then the safety switches, or the ignition switch is probably the problem.

Be sure to wiggle the shift lever kinda roughly while trying to start it, to see if the neutral switch might just be out of adjustment.

Van