Electrical problems

[Pro Star Cummins]

Need some guidance to fix electrical problems.
The city horn and air horn,jake brake,quit working.
The tractor abs light and traction control lights
Are lit and some dash cluster lights don't work . The
Patel buttons on steering wheel don't work .
Cruise doesn't work , it did work before but always threw a
Intermittent fault code . We always could clear code,but it
Would return. We also cleared abs light with DLB , but this
Comes back. Pulled on wires , checked fuses, can't see any
Bare wires. Can cruise control switch cause these problems?
I'm thinking it must be switches in steering wheel pad.
Is there a way to check them ?
Any help would be appreciated . Thanks