73 Dodge Dart Sport Fuel Gauge Wiring

he gauges are repairable but it aint cheap. Once you get the panel out you can check the gauge connections to the printed circuit board.
If there was a Ford type catch on the wiper knob it would be right behind the knob , not behind the panel. Look again for a small set screw in that knob.
The headlight knobs are made onto the stems because the get pulled. Its not supposed to pull off the stem. The wiper knob doesn't get pulled so the stem is built into the wiper switch.