On my 2005, the ABS "valve' assembly is on the frame cross member just fwd of the drive axle. I have not seen the ABS controller.
I try to photo document all the parts on my coach (sometimes to identify what they are).
I think my ABS controller is mounted near the ABS Valves (In need to crawl back under the coach to verify). I seem to recall seeing the "frame mounted" unit near the ABS valve assembly and recall noticing the wiring that goes into the bottom of the controller not having any "weather protection'". But I can't find any photo of this in my files.
If I can get back under the coach this weekend, I'll try to locate the controller and get some photos (but this still may not help you as I have a '05 Patriot and you have a '06 Monterey).
Good luck