This is a 76 k-10, Worked fine the other day, but now when you try to start it, it will crank and continue cranking unless you turn the key back, also doesn't supply any power to the ignition. Would that be the ignition switch, or maybe a key cylinder bad?
Ok, its hard to tell from your description exactly what is happening.
If, when you turn the key to crank, it sticks in that position, then its probably the lube in the rack and pinion under the key cylinder has stiffened due to the cold or age and just needs some lube.
If it continues to crank even when the key moves back to run, then the switch is a distinct possibility, but I would take a long hard look at the wires on the starter solenoid.
Sounds like some of them might have gotten crossed or shorted.
As you probably know, the ignition switch is not under the cylinder, its in a box towards the bottom of the steering column.
Not supplying power to the ignition could still be a wiring problem at the solenoid.
And its easier to check those wires than the ignition switch.
The lock cylinder is not a problem in either situation. If it unlocks with the key and turns, then its pretty much fine.
