Not teaching you to suck eggs old chap, but a wiring loom is a pretty simple piece of kit. There's nowt to it really that a multimeter won't find.

Might I suggest you get a wiring diagram and sit down for an afternoon of prodding? Wiggle whilst you test, and any loose connections should show up.

If you were closer I'd offer to help - my FJ is 19 years old and needs regular wiring tweaks to keep all the electrics working. In fact I neglected this a few years ago, and the main loom melted

I now check and clean connections every year!
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