Dash problems

The 65 Dart has the voltage limiter incorporated within the gas gauge. If it's bad then your gas and temp gauges won't work. Real Time Engineering and others have a solid state retro fit, but you'll have to open your gauge, modify the inside of the gauge where the regulator is to use their external retro fit. Even doing that there's no guarantee that your gas and temp gauges are still good. If they got the full 12 (or more volts) when the regulator went south, they are probably fried.