My 5th wheel does not power off of my vehicle when connected to it. A couple of times after it has set for a period of time, with no power connected to it, the 12V battery needs an assist to get the f...
You didn't say what type of tow vehicle, or if you did I missed it. On some trucks, such as my Chevy, the company installs a dummy fuse in the fuse box. The big fuse box under the hood up by the firewall. You have to take out that fuse and install the one that comes with it. Not sure why they do this, but that's the way it was on my '05. Worth taking a look at.