Chyrsler Dash Flashing

2001 Chrysler T&C, 211K miles, 3.3liter. After about 50 miles of driving the warning lights all flash then return to normal with the exception of the seatbelt light which remains lit a few seconds more. Then 4 or 5 seconds later a chime sounds. Additionally, the speedometer needle spun around fully until it stays against the peg while driving (just hangs there when engine is off). Other than that everything seems normal, i.e. headlights do not flash, lights in center stack for radio, clock, A/C etc. appear unaffected, cruise, widows, locks all seem fine. Our mechanic “reset” the dash once but problem returned - he assures me there are now safety issues. Anyone have any thoughts/suggestion ? Appreciate any help !!

Rty reseating the dash connectors. Also, I would make sure the battery connections are clean and tight and the grounds and chassis grounds are clean and tight.