2001 Electrical trouble.

I replaced the battery today on my van.
The old one completly dead. After replacing
the battery I attempted to start the van. It
cranks but will not start. The strange thing
is the headlights go on immediatly when I turn
the key even with the headlight switch in the
off position. Also my odometer display is out.
Everything else functions ok. I pulled all the
relays thinking one of the contacts was sticking,
but had no luck the headlights remained on. All the
fuses are good. Can't figure this out. Could it
possibly be the ignition switch? Any suggestions
welcome. Thanks in advance.
Sir Joe.