First: as not cranking sounds like "heavy ground" per Rocky's statement.check the ground straps, def one at the gear box end. I have at least 3 installed..
Second: well depends on your starter but stock has this solonoid close to the Ignition modul, is a kind of very heavy relais. The relais connectors inside might be corroded, hence a considerable voltage drop, no power at the starter (worn out MODERN starters do the CLICK noise when bad). More difficult to diagnose, you would need a volt meter AT THE STARTER connectors, try to start an measure voltage under Starter key in START, i.e. under LOAD!
Matthias