99 venture loses power with a good alternator.

loses power with a good alternator. driving the van and the headlights go off loses all electrical power & shuts down. can jump off & goes dead when you remove jumper cables. had alternator tested tests good every time. have been having an issue with the park lights not working all the time also. can move the fuse block under the hood & move the middle set of wires & they will come on.when the park lights do not work neither do the tail lights or the dash lights.