90 new yorker elec connector problems

All at one time, the door locks would only unlock, the wiper delay quit working, sometimes the gauges act weird, and the granddaddy, the headlights came on but the headlight doors wouldnt open!! Chrysler dealer charged $100 just to look at it, said they didnt repair anything, but it was all working! I think I have a bad plug, connection somewhere, probably something they unplugged and reconnected. Now 2 yrs later its acting up again. Could someone point me to the most likely suspect?