Ok, then the cable supports a 50 amp service, and your present 3 prong plug is only providing power to half the trailer's circuits. you can wire the 50 amp plug per the diagram above -- you can always use a 50 amp to 30 amp 'dogbone' adapter if you need to plug the trailer into a 30 amp (or even a 20 amp service, with the use of the additional adapter from 30 amp plug to conventional three prong plug.)
2007 Tour Master T40C
Acura MDX toad
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