1994 e150
 

my 94 e150 cargo van stright 6- will not keep a charge replaced altanater and battery the needle will not move very much also. had it running put my foot on the break to move it and it died.[only once].replaced battery [new]it killed a cell it still will not keep a charge.hooked trailer wirses to it for my trailer the wireing was a mess.mabey a short?
:help: