12.7 Detroit 96 w9 jake brake switch wiring

I just bought a 1996 w900 with a 12.7 Detroit. For some reason my Jakes seem to be working wrong. My on/off switch does nothing and my selector switch works on high and low and the middle position seems to be off. Any ideas?
The motor is freshly built, the wiring harness from firewall forward is all new. The truck came from the factory with an 11.1 Detroit and was swapped before I got it to the 12.7.

 

The 12.7 has three stage brakes so it’s not that. I may need to replace switch’s....

 

Motor is fresh. 200 miles on it. The way I understood it was that stage three was one and two together? I have no idea if the solenoids were replaced with everything else. It is a new head but I don’t think Jakes come with a head.

 

Let me see if I can explain this better. My on/off switch does nothing to change on/off. The level selector switch has three positions. The top and bottom positions work and the middle selection seems to turn Jakes off.