Elec. problems 74 Dart
Stoplights..........most all stoplights on U.S. cars of that era went through the turn signal switch.
So check right at the stoplight switch or at the turn signal switch connector
If you are getting stoplight power there, going INTO the switch, AND if the turn signals function, then it's a problem in the column signal switch.
Temp.........Does the fuel gauge work?
Did you try shorting the sender wire to ground with key "in run" and see if the gauge deflects?
If the fuel gauge works, possible problems are.....
Broken connector (insided) the molded sender connector
Corrosion / loose in bulkhead connector
Poor connection at the instrument cluster PC board pins and harness connector
Loose / corroded stud / nuts on the gauge to panel
If the fuel gauge does NOT work this could get deeper