Dodge Repair: 2000 Caravan interior lights, point thanks, headlight switch

Question
My wife left the windows down and a storm came.  The van now flasehes every light it has (interior & exterior) when it is started.  All lights return to normal when the headlight switch is turned on.  I realize it probably has a short, but was wanting a starting point.  Thanks.

Answer
If the inside and outside lights are flashing  that might be a body computer  see if u can feel some water under the driver side dash there will be 2 big 30 way connectors going into a computer.I live in the Atlanta area I would be glad to look at it for u.