Not cranking 7.3L 1997

batteries are under a year old as is the starter and alternator and GP relay and ecm module(brain). Truck was running fine tonight something is wrong. When you turn the key on it would go from normal to as though the key was turned off, and now when you turn the key to the on position the GP relay and something else click continually every couple seconds and it has a large power draw when it clicks as the charger i put on the batteries would jump to 20+ amps. will not crank, and acts as though the batteries are dead or nearly so. IF i put the charger on the 55+ amp charge 150 amp boost the battery gauge shows to the highest "normal" on v. Leave it on a 2amp trickle and go back 20 min later and it acts like the batteries are dead.
Please any clue whats going on?!
tried jumping the starter relay and it clicks once nothing more.