2000 Kenworth W900L Jake Brake Wiring

I have another question on my 2000 W900L with the 12.7 Detroit. It looks like the Jake switches were added to the dash, there are new holes drilled by the differential switch. But the jake seems to only work on the 1st stage no matter the switch position. Not sure if it is wired properly or if the switch just doesn't work. Is there a wiring diagram somewhere to compare how these switches are wired. Or where should one start? Really need the 3rd stage working, 1st stage doesn't help any coming off of mountain passes. Thanks for any info!

 

No I did not.

 

Ok Sounds good. The truck has an after market steering wheel, it must have had the smart wheel in it before and that is why the switches got put in. But they did not use a new harness, just wired them up. The cruise switches are also just wired in.
Anyway last 6 of vin 359589