You have also indicated that you have no 120v power when the inverter is turned on and no shorepower or generator power is present.
This situation would indicate that your inverter breakers are not set, the house batteries are not charged, the big fuse that might be in your wiring between the batteries and the inverter is blown, or the inverter is not working.
My rig has two Class T type 300A fuses between the house battery and the inverter. One located near the battery and the other 20 feet away in the inverter area. If one of these fail, there is no 12v power or inverter power.