Clearly you are an accomplished enthusiast, thank you for the diagrams.
That is a shame that your Ariel doesnt work, I am unable to help you with that sorry.
What I will say is that over 20 years ago that was the problem with my XJ tho it was a case of the original owner trying to force it closed and buggering the mast up.
So I enquired at Chrysler Jeep UK the local dealer. The whole thing rocked me on my heels, I was quoted around the £400 mark. Absolutely crestfallen, I did a deal for about half that price with the manager as a trade/staff discount.
When it arrived and I had the wheel liner and the wheel removed by me it didnt bloody well fit and looked totally different than the original.
JEEP UK had changed it to a generic chinese looking knock off. Very upset I spoke to the manager who has since then become a great friend. Anyway he rechecked for me and found there were only about 8 original OEM units in the whole country, as I said this was over 20 years ago. I fitted the new OEM and have always kept it clean and lightly oiled. Terrified of it going wrong.
So I understand you taking the fuse out and can only assume you have an internal electrical fault. You are really stuck. The OEM ones are very substantial with a metal body/case and a special plug connector. It may be possible to either take it apart and check for the fault or have an electrical shop do some tests, either way you have my sincere sympathy. One of my abiding memories is having my two large dogs in the back and the stereo on driving to Clumber Park in the sunshine and the dogs going absolutely mental when they realised where exactly we were going. lol.
If you are near Chesterfield and you need a great factory trained mechanic let me know and I will forward you his details. Kindest regards. Ogri.