I believe I have an electrical shortage in my 2003 dodge 1500 van.

Every couple of weeks it will stall
upon first starting it when I take it out
of park or turn on the headlights.  
While this (shortage I believe) is
happening, the top rear brake light
stays on and the dash, radio and
brake lights will flicker when I push
on the brakes or hit the gas while it's
in park.  The dealer replaced the
headlight switch but that wasn't it.  
They now want to replace the ignition
switch?  They got the situation to
occur again when they moved the tilt
stearing column up and down.  Any
ideas...this has been frustrating.
Thanks