Behind the fridge there are "hot" wires coming for the WFCO area, they are connected to different wires:
- The 120-VAC hot wire, from Romex, is connected into the more flexible Air Conditioner cable. (The lone cable, NOT within a "bundle").
- The hot wire for 12v, going into the loosely wrapped bundle of "other wires" going up to the front shell.
- The hot wire for 12v, going into the loosely wrapped bundle of "other wires" going up to the rear shell.
In order to distingulsh the front shell "12v supply" from the radio's speaker wires, avoid wires coming from above (the stereo set), and look for a black wire from either under the sink.
Only one "12v" wire comes from the under-the-sink bundle, to be joined to the lift arm wire by a nasty and unreliable compression butt connector. (I think that the insulation on those connectors is blue/clear, although I can't check right now.) There are other butt connectors for the stereo speakers, but the speaker wires wires are smaller and they come from the stereo set - not from under the sink.
When you have the likely candidate, you can give that butt connector an extra squeeze with a long handled pliers (not a needle nose). Or (better) you can cut out that but connector and replace it by a WAGO spring-lever connector instead (either a 2-port, or a 3-port with one port left empty).
If you cut it out, you can verify the correct wire ID by pulling the fuse for front shell, with black wire (form under the sink should go from 12v to dead.
If it's not that butt connector, then you have a broken wire within the "up" cable, or at a possible connection between the "up" wire and the front shell roof at the top of the upper loop, or perhaps higher The diagram seems to show that the back-side patio light is wired direct to 12v, not through the interior switch. The fact that it work with "wiggling" implies the up wire or it's terminating connection.
There is a less likely "problem" behind the back side porch lamp, or the junction which feeds the interior fan. Does that street-side porch light work without "wiggling?
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I hope its the nasty butt connector behind the fridge, that's easiest.