RV Repair: open ground in ambulance, gfi outlet, ambulances

Question
i have a fleet of ambulances one is showing a open ground when i test the outlet the gfi outlet next to it is not working what can i do

Answer
I need to know if it has ever worked. Having an open ground means that the ground has been lost. The best way to try and find out where it is, is to start at the 110 vac panel and checking continuity from there to the outlet. By doing this with a meter you should be able to locate where the trouble is. Was the g.f.i. just installed? They need to be wired correct with a supply side and a load side. Test for continuity between the frame and the 110 vac panel as well. This could be somewhat hard to find and you may be better off taking it to a repair facility that can work on electric.