Dead short?

1970 has a different column connector than my 1969 Dart had (and current earlier cars). I think you have the key switch in the column. I suggest getting a multimeter (free at HF), gound the black lead, set the 200 ohm scale. With BATT- disconnected (to be safe), touch the red lead to each pin in each connector. If it reads < 5 ohm, make a note. Check a wiring diagram. Some of those might be intended to be grounded (then OK). If a supply wire, it is probably shorted to ground. A 15 W bulb would measure > 10 ohm [P=(V^2)/R].