Bought a 73 Challenger last week. The head lamps, tail lights, horn, dome light, speedometer all work. The oil pressure gauge, water temp, ammeter, fuel gauge, tach, wipers, turn signals, don't work. The seller said the dash voltage regulator may need replacing. Where is the dash voltage regulator located? There are some electric connectors/plugs that are not being used under the dash...could this be the problem? Near left side of glove box (six spade connector), and next to steering column three plug connector not being used. Any suggestions, Thank You