RV Electric - I am obviously a novice

For good of the group, I will update this subject and hopefully it might help someone trouble-shoot in the future. I bypassed the entire power supply to the bed lift system. I used a different 12v power supply and wired it directly into the circuit board that feeds the Happijac bed lift. IT WORKED. So, something definitely happened to the 12v power supply that fed the system for the 6 years we have owned this this Forest River toy hauler. Although my meter indicates the original wiring is getting power to the circuit board that feeds the bed lift system, I suspect maybe the ground is loose somewhere. I have no idea how to identify where the problem lies. So, my plan for a permanent solution is still "in the works." My gut told me failure of a Happijac lift system component was likely the cause, but in this case the trailer wiring was DEFINITELY the cause.