99 Dodge Durango

The feature that keeps track of mpg and
estimated miles remaining on the ceiling
indicator, you can press the right hand button
and it steps through items like Temp outside,
direction, N,S,E,W and remaining miles.
The problem is: I reset the unit back to '0' and
try to start the engine, it cranks but does fire.
The odometer indicated ' no gas', but i know
there was a half of a tank of gas because it
was showing on the fuel gauge before i reset
the unit. If I remove the hot wire on the battery
for a minute and then reconnect it, something
gets reset and the SUV will now start.