That steering column connector should have a red wire (heavy gauge) that gets battery voltage all the time. This red wire goes the ignition switch as a feed for most of the vehicle's accessory circuits (HVAC/radio/etc) and of course, the ignition circuit.
From that dash harness connector the red wire goes to the bulkhead connector on the firewall and has a fusible link that connects it to the starter relay where it sits on the same stud as the positive battery cable.
If you have an issue with broken/frayed/corroded wires on this feed, it would result in low/no voltage. You can either trace the big red wire or replace it...either way need 12V+ on that red pin going into the harness. It is very important this is at least a 10ga wire as it will take all the current that feeds the aforementioned circuits as well as charging the alternator.
If you don't care about this and just want to hot wire the car to start...you can run a jumper with a toggle switch (to turn off the car) from the positive battery terminal or starter relay stud to the hi side of the ballast resistor (blue wire). You will then need to use another jumper or ideally, a remote starter to jump from the positive battery stud on the starter relay to the IGN pin (yellow wire) to engage the starter motor. All this normally the ignition switch in your column does. :-)
The best thing would be to find out why you have the voltage loss and where the heavy gauge red wire went (broken/corroded wire or connector). Easiest thing to do is get a 10ga or better wire and splice a 16ga fusible link inline for safety. Run this from the positive stud on the starter relay through the firewall to the red pin on the steering column connector. Provided the ignition switch is OK, this should get you running and keep the accessories working as well.
