Have RV Questions? Ask an RV Mechanic Online.
Hi my name is Robert..
The jacks are normally wired directly to the battery, when you are plugged in the converter will charge the battery and make the DC voltage. SO I would get a meter and verify the voltage, if the voltage is low then it could be a converter issue. IF the voltage is good then it could be a tripped breaker, below is a picture. Sometimes they will put one on the cable from the jacks to the battery AND from the converter to the battery. As a general rule they like to stick them 18" on the frame, most will have a small tab that pops out on them however some are thermal and self reset. With a volt meter the voltage should be the same to chassis ground on each post. It should actually be close to the battery voltage. I might also have the battery load tested, if the battery was bad it may not want to accept a charge from the converter, most auto parts stores will load test them for free.
IF you have good voltage at the battery and the breakers are good then it could be an issue with the jack motor.. Really have to verify the voltages to see what is going on... IF you have more questions or concerns please feel free to contact me... IF you are satisfied with my efforts please feel free to select a rating, it is the only way I get credit, also feel free to follow up if needed.... Robert