Vehicle won’t start with ignition switch

[Geordy]

This M1083A1 ignition switch won’t work, we have to use The Cab Batteries Disconnect Switch to start and turn off the truck.
Relays are good
Also tried to use another ignition switch and still didn’t work
Any ideas?

 

[Ronmar]

Ok what exactly do you switch or jumper to start the truck? By cab battery disconnect are you referring to the red guarded sw to the left of the steering column? That sw does 2 things.

1. it opens the battery disconnect relays in the box to the rear of the batteries adjacent to the manual disconnect sw.

2. It also disconnects power from both the inside and outside ignition switches.

so my second question would be, has the outside ignition sw on the passenger frame rail been left on?