Chevy Workhorse W22 Chassis Wiring

Have 2006 Tiffin Allegro Open Road. Have intermittent problem with automatic jacks. The light on the Atwood Dash Panel that indicates that the vehicle is in "Park" works intermittently. When it is out the Atwood control panel thinks the vehicle is not in Park and won't allow the jacks to work. Dealer was no help because it happened to work while in the shop (no surprise!!!). I called Tiffin and they sent me a picture of the Atwood wiring junction box under the dash. I determined that the green wire coming from that box to the Atwood dash panel was tight and functioning properly. I cannot get anyone to tell me what wire color and where the wire goes from that junction box under the dash to the signal source. Does it go all the way to the transmission or to the steering column or what? I want to trace it out to see if something is loose somewhere so that I can replicate and correct the problem. Tiffin gives me a Workhorse number to call and they refer me back to the dealer!!