When I open the door to my 03 Grand Caravan, dome light comes on and odometer is visible. As soon as I turn the key all goes dead. Is this a battery issue or a starter issue or an alternator issue? Thanks.

Most vehicles will display the odometer when you open the door. It's so the service department can get the mileage reading without the engine on. Have the battery connections checked for corrosion. You can get the battery charged for free at most major part stores.

sounds like the battery is dead. check battery and charging system.

Turn on your lights to see if the battery is dead. If so, clean the terminals, have the battery checked at any parts store or Wal Mart, and check to make sure your alternator is functioning properly. If not, get an electrical schematic and check all of the voltage inputs and outputs on your ignition switch. That will almost certainly point you in the right direction. If you don't know what I'm talking about, (or can't crawl around on the floorboard in strange and painful positions) you might want to take it to a mechanic.