Something is broken...... Your Jacks are driven by a hydraulic pump which is powered by a 12.5 volt DC Motor. This DC Motor is powered from your House Battery Bank. One possibility is that your House Battery Bank is discharged or Kaput.....meaning, does not produce 12.5 DC volts under load and so your jacks will not work. However, when you plug into shore power, your Inverter supplies the 12.5 volts DC across the battery bank and your Jacks will work. Check for 12.5 VDC on your house battery bank under load (Jack motor on) when NOT plugged into shore power. If 12.5 VDC is not present....you have defective batteries. Rook
When you get a chance to dance, or sit this one out......I hope you DANCE!
98 National Tradewinds 7370, powered by a 3126B 300HP CAT Turbo, Freightliner XC chassis