DH went over to our storage spot to see if he could get the monitor panel working. Bob gave us advice as well as our HiLo dealer. When he was underneath the other day he lubed up the cables. DH saw wires but wasn't sure which one was the ground wire. The wires run to both the black and grey water tank. The white wire is the ground one. The terminal attaches to the tank. DH put a jumper wire from the terminal to chasis ground. Drill a new hole in chasis (screw).DH used a solderless connector. They black tank still reads 3/4 full when it is nearly empty. Not a problem as we mostly do weekends with our camping clubs. We have a blue dump tank for when we do one week a year campout. We had J&R put in a new exterior refrigerator vent.as it wasn't sealed properly from the factory. I understand the ground wire runs in back of this vent. If you have to remove this vent it destroys it. Some day when our refrigerator needs to be removed for replacement we can get at this wire. We have the used monitor panel if anyone needs this. Just pay postage. Wouldn't have needed this part if we asked for advice first. Hope this makes sense what I have written up. Maybe it will save someone from having to figure this out.