i know in the older body style, the wire powering the cig lighter port was short enough that it usually came unplugged whenever the panel was removed. i don't know if thats an issue in the newer vans.
what you should do is test to see if the contact in the center has power AND if the outer body of the socket is grounded. a simple test light can do this for you. from there, a problem on power getting to it can be bypassed with a new wire going through a fuse to the battery or distribution block. if its a ground problem, just run a new wire from the ground side of the socket to a good clean piece of steel thats grounded.
if both seem to be connected, your problem could be a dirty/corroded socket, which can be replaced for pretty cheap at your local parts store