I would look around your battery(ies) for a fuse or circuit breaker. It would be close to the battery. Some circuit breakers can be reset. Small 1/8 diameter button top push.
This fuse or circuit breaker would prevent your tow vehicle from charging the battery,
Next check your system for proper polarity. It is possible that the batteries could have connected improperly and blew the reverse polarity fuse on the converter, if equipped.
When plugged in check output of the converter in the DC distribution panel for voltage around 13+. If no voltage is present check coonverter input for 120 volts AC.
Check converter output for voltage.