12 Pete 386 Starting issue

Working on a 2012 Peterbilt 386 with Paccar MX13. When trying to crank it keeps dropping power to the "relay"/solenoid on the starter. I can put power to the relay and cranks over fine. Has constant 12v out of the key switch to starter, but power comes and goes at the relay. I replaced the starter interupt relay behind the cluster with a known good relay. I cant seem to find any good wiring diagrams for this style system. Any help?

 

Ended up bypassing the starter interupt relay behind the cluster. Even with multiple good test relays it wouldnt start. Put a jumper wire in place of the relay and it cranks fine everytime.