Parking lights and turn signal trouble..

The highlight switch has a rheostat that brightens or dims the illumination circuit as the switch knob is turned. Includes dash lights, ash tray light, shift indicator, radio, etc...
The rheostat may be fried or sometimes just a good cleaning will cure it. New headlight switch is the most common cure.
Due to the way this circuit is wired you could see the rheostat working at the fuse with a simple test light ( if it works ). If it is dead you wouldn't see any power at that fuse.