Mileage not showing on the dash

Usually this is caused by cracked solder joints in the dash. The odometer has its own plug back there. If you know any place that does circuit board work, you might be able to get it re-soldered. Maybe a computer repair shop or somewhere like that. Otherwise, you could try getting a junkyard dash (eBay or the local u-pull-it) or get a new one. Sometimes it is just a loose connection, but I would not count on that. Good luck.