Columbia has no power with key in ON position

Throw a charge on the batteries or a jump and see what it does.

 

Voltage reading at battery connections on starter? Then three terminals on right side on fuse box?

 

Sounds like a bad ground. That’s the standard answer for all electrical problems. Lol. Follow the grounds from battery to frame, Should be the 2 big cables and hopefully 1 or 2 small wires, for the ecm. Carefully remove the nut from the post on frame. Might be rusty. Don’t want to break it. Wire brush and grease everything and put back together. Hopefully when you turn key on your dash warning lights and buzzer will all be working, and it’ll crank. If not, leave the key on and start wiggling wires, listen for the buzzer, might get lucky and find a bad or broken wire.

 

Yes positive to starter solenoid on starter. Dave is probably thanking about low voltage disconnect but I don't that that knocks out the ignition switch.I was assuming you had no power in cab.
Maybe check fuses - breakers and for power the ign switch?

 

I’ve had loose battery cable connections but that only dragged the starter at start up. Could be a loose battery cable somewhere also, like by the starter……. I would chase down the cable connection ends. Also, my current truck sometimes won’t kick over, I’ll cycle the key, but doesn’t kick over, so I’ll cycle the key again maybe once or twice then it kicks over. I’m still trying to figure that issue out.

 

In a Century there are two master relays, one powers the engine and the other everything else. Not sure if the Columbia has the same setup. Although I would think if it was the engine one, then all of the accessories would still come on.
I’ve also had a bad ground that would stop it from cranking over, but everything else still came on initially. But easy enough to clean and check that connection.