12V Electrical Issues (Noobie Help)

Dominic Rouse

New Member
Howdy everyone..! My first post and a noobie to the RV world ;)

Took our 1988 Ford Fleetwood Rallye motorhome our of winter storage for the first time last week and notice that the 12V cabin lights were not working. Then found out that all of the appliances (water pump, tank level monitor lights, stove fan, etc.) were not getting power either.

So, hooked-up the generator and tested. The power indicator on the 30A surge protector plug we purchased revealed that we have a ground fault. Inside we confirmed that the cabin lights all work, the stove fan and the AC fan also work, but still no power to the pump, tank monitor display.

We tested the 120V receptacles and they all work. There is one (1) GFI wall outlet and it was tested and reset without issues. Checked the cabin battery and has a full charge.

Two (2) red cables are connected to the +ve terminal and the sine wave converter red cable is connected to the +ve and black to the -ve (photo attached)

Checked the converter coil relay to see if it wasn't switching from 120V (generator) to 12V (cabin battery) by pushing it back and forth, but no dice.

Stumped as to what could be the issue or what steps to take next. Any advice or shared similar experiences would be greatly appreciated.

20180509_071951.jpg 20180421_132415[1].jpg

Dominic Rouse

New Member
Ok, going to also check each fuse for continuity. An electrician friend suggested that although the fuse bar looks intact, it may have connector issues. He also made a logical comment that if one of the circuits, e.g. the cabin lights under 120V, actually receive power, then we should use that fuse on the water pump/tank monitor circuit as this would confirm if the fuse is the issue. Also, we're going to test the lights circuit under 120V generator but with the battery leads disconnected, which would point to the converter as the problem.

Any other troubleshooting methodology ideas..?
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