2 more things come to mind. Always try the menu, control, ditch lights, on with the remote. Just incase they were shut off like after using the engine in a helper mode. Resetting the engine usually does that. Yes, the PS3 LED ditch lights only come on with the engine moving.
Some MTH ditch lights (and other lights) are supplied power thru springs that make contact when the shell is tightened down. I have seen these springs out of place, both from the factory, and from users removing the shell and not taking care when putting the shell back on. I've even had a cracked spring holder bracket.
Another thing if you're inside, is to take small DC voltage ( under 3 volts?) and test the LED lights directly. I have a holder that I keep on my bench that usually has two AA batteries that have been inside a remote and are heading for the garbage. If they have any volts left, I put them in this homemade tester. No sense in going nuts searching, if the lights don't work directly.
