I finally found it. Thanks to all for the help. Customer service had given me the impression that it was at the end of coil wire tied to the steering column and in plain view from underneath. Instead, it is on the end of a 6" pigtail not very close to the steering column and best accessed from the top. I have not found a label yet but everything else matches, including the wire colors that Freightliner gave me.
Thanks again. I will probably have more questions as I figure out this rig. It is a big step from the truck camper I have been using for the last 20 years.
