Horn doesn't work. I've established that if I manually ground the Purple/Black wire (with key turned to "On"), the horn does work, so somehow that P/B wire is not getting its ground. I removed the Steering Wheel pad and cleaned up the contact points, but no dice.
What should I check next? When I had the wheel apart, I did notice that the brass center nut on the column had a hole in the center - is there supposed to be a spring there or something?

Thank you!

If you remove the driver's side under-dash trim panel and look at the side of the steering column you see two brass "fingers". These connect to ground contacts inside the column. Make sure the connects are clean and tight and fingers are not corroded

Cheers
DD

the hollowed brass contact is normal. No spring. The brass tab behind the foam pad makes contact with it when you press it.
you might need to bend the foam pad's tab a little so it does make contact.

Are you talking about these “fingers”? They were really gunked up. Haven’t gotten any sound yet but will mess around with them
a bit more

Edit: ok, when I manually press both of them against the steering column,
the horn sounds. However, it seems to do this independent of the horn button. How is this supposed to work in terms of finger position?

More digging - here’s a thread from jag lovers that gets into details:
https://forums.jag-lovers.com/t/xj-s...tact/344208/13

it appears that the plastic sleeve around the steering column, which may support a shielded spring, is broken, so I have continuity between the upper and lower finger contacts, which should only happen when the horn button is pressed. Sounds like the only fix is a new steering column.

I’m leaning towards rigging up some kind of aftermarket horn switch to give ground to
the purple/black, and calling it a day.

Is the steering column ground necessary for anything other than the horn?

Simple solution for now. One wire tied into the purple/black, and the other tied into ground.

That's been the 'temporary' solution on my car since about 2010.

This may help you.
https://www.jaguarforums.com/forum/x...1/#post2676029

Dave