Brake master 9100 problem

12 volt feed from ignition power source not providing 12 volts to air compressor. Of course, no compressor, no brakes. System installed on 2006 pace arrow in 2006 and has always worked great. My problem is I can’t find connection under dash to troubleshoot. Tried tracing blue wire from compressor but so far, no luck.
Anyone have a wiring diagram of under dash fuse panels for w22 workhorse or advice on where your connection was made.

Doug