I've been chasing the multi-warning syndrome for quite a while now, new battery, cleaned the grounds behind the headlights, ground posts in the boot, etc. Still no joy. The current (LOL) problem I'm curious about: Has anyone noticed a reduction in horn performance connected with this syndrome? I rarely use the horn, so can't tell how long it has been on the fritz. I only have the high note, which by itself is weak and flat. Sounds more like a Renault Dauphine city tone than ANY kind of Jaguar. I looked briefly for the low note horn, but haven't found it yet, just to see if it's getting a signal at all.

The horns crap out over time. They are on the front left side. You can get at them by removing the fender liner or the lower radiator cover. I was able to order inexpensive aftermarket replacement horns from Amazon which were easy to adapt and have worked fine.

Good Luck
Jeff

"Renault Dauphine". LOL!!!!! I remember those. My mom test drove one from a dealership...must have been around 1960....it was comical. She went and bought a new Rambler America s/w.