Thanks for the responses from everyone. I still haven't heard back from Renegade, so I decided to plug the toad in a see what happened. Fortunately, all the lights worked as expected. So, it appears that the MH pins are coming from an electronic controller with open collector outputs that need a load on them to properly measure the voltage. I'm going to try one of the plug testers and see if it works, I suspect it will because its LEDs with current limiting resistors should provide sufficient load.
I did encounter something "dumb" when I attempted to plug the umbilical cord into the MH for the first time. The 7 pin connector is installed in a bracket that is part of the Reese hitch, and sort of tucked under the rear fiberglass cowling of the MH. The 7 pin connector is a Reese 85219 (like this
https://www.walmart.com/ip/REESE-852...&wl13=&veh=sem ) with a spring loaded cover. When I raised the cover to insert the umbilical cord, I discovered that the thumb lift part of the cover hit the fiberglass cowling of the MH before I could raise it far enough for the locking post of the umbilical cord to clear the corresponding part of the cover that's supposed to prevent the connector from backing out once fully inserted. Dumb...
Since I'm the second owner of the MH, I don't know if this was factory installed (I think it is) or owner installed, but I do know the previous owner towed a toad. So, either Renegade installed and never plugged an umbilical cord in it to factory test it or the first owner had it installed and simply pushed the connector as far as it would go (which by the way wasn't far enough to engage any of the pins or lock in place). I "fixed" the problem by rotating the Reese connector 180 degrees, so the spring cover pulls down, allowing the cover to open completely and the connectors to properly mate. Since this is our first MH, I guess it's all part of the learning curve... Thanks again for your responses!