Its a 1988 e-350 7.3 cube van
it drains all the way, nothing at all happenswhen I try to start it ,the guys I brought it to said it was the ignition switch, so I had that replaced and it did nothing to help the problem.....what is going on?????

 

it needs to be checked for a parasitic draw with an ampmeter,then remove fuses 1 at a time to find it