Truck won't crank/start. Dome light flashing. Relays clicking
 

Hello all,
I'm new here. and my 99 f250 7.3L diesel is acting up. Dome lights flash like a hazard light every time the door is opened, and there is also a clicking sound from under the dash, kinda like the relays are clicking on and off or something. The engine will not turn over nor start. The instrument cluster starts going totally crazy when ignition switch is in the on position. I have checked the battery connections, and even charged both batteries and they appear to be in working order. I have changed the glowplug solenoid and all fuses appear to be working and functional. Please help

Those years were known for the windshield leaking and corroding the components under the dash just over the parking brake area.
A quick inspection of that area for rust and corrosion would confirm that suspicion.
Until it was determined what was going on , it drove technicians crazy with unusual things happening.
Can you check if this condition is present?
If it is, the solution was to have the leaking windshield repaired and replace the GEM module.Some folks were successful cleaning the component,but not too many.
A little FYI, they leaked right from the factory.