That Cable Tracker is the way to go. It puts a high frequency signal on the wire and then probe for the signal. Il allows you to follow the routing of a wire through the walls. Given the convoluted way some RVs are wired, this can be a very handy tool. It will work with 120 v circuits or 12 v circuits. By putting the signal on the shield, you can also use it on the coax in your tv inputs.
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