Are you plugging the trailer into a 15 amp plug (with an adapter) at home, or a 50 amp and using an adapter for the generator?
2007 Chevrolet 3500 CC/LB Duramax/Dually 4X4 Mine r4tech, Reese Signature Series 18k +slider, duratrac, Titan 62 gallon, diamond eye, Cheetah 64
2011 Keystone Fusion 405 TrailAir & Triglide, Centerpoint, gen-turi, 3 PVX-840T, XANTREX FREEDOM SW3012, G614
The Forum cops aren't going to kick in your door and take away your keyboard.
They only try to do that with the weight police.
2012 F350 PSD CC 4X4 Dually to pull 2006 LE3905
When I run My Honda 2000i, my "plug in" monitor shows "open ground", But everything works. When I run the onboard Onan the monitor reads OK. Could there be some sort of protection built in your rig somewhere that won't allow power if there are any faults ??
2008 GMC 2500HD 4X4 DMAX CC
2004 Thor Wanderer Wagon 247WTB
2006 TE450 Husky
2007 Rhino Sport Edition
Does the Toy Hauler have an energy management system?
Is there a transfer switch?
I'd check the output of the Yamaha with a polarity tester, and compare that to shore power and to the built in genny.
I'm not aware of any kind of energy management system, and have not seen a transfer switch. I've looked in the onboard generator compartment and also on the fuse panel ...
I have also put my electical tester to the portable generator and it does read 110.