dash gauges and turn signals acting up

Nearly everything electrical in older vehicles depends on a chassis ground path through the nuts and bolts holding it together. This applies to most inst' panels. If it has a metal housing it isn't going to function properly while dangling from the harness connectors unless you add a ground jumper.
The front park lamp fixtures either use chassis ground through a metal grille or they are mounted in plastic and have a ground wire to the radiator support.
Saying what car this is might get a better response. Good luck