LVD is not cecu controlled on your truck. Might not even have one.
LVD does not have anything to do with the starting circuit anyway,
The starting circuit goes through a start enable relay that the CECU controls. If voltage drops to the cab the relay trips and power gets cut to the starter. Once that happens the dahs gets full power again so it sends it to the starter then gets low voltage and trips the relay. Hence the click click click.
Root cause is too much voltage drop to the cab. Clean the cab grounds and powers at the starter and up on the firewall cab mega fuse box.
You can also pop the speedo and tach panel and bypass the cecu controlled start enable relay. This will let the engine crank til there is no battery juice left regardless of the voltage to the cab. You can jump it with spade terminals and a short piece of wire. The fuse panel lid will id the relays behind the speedo/tach.
After you jump it only the key controls the start circuit and the CECU cannot intervene for starter overheat/ rpm starter disable.