The scales actually make sense. They show how heavily you stomp on the pedal, anyway.
Didn't the Jag dash complain about "bulb failure" etc all the time?
Yeah, if you put the wrong lightbulb in one of the exterior lighting sockets or didn't clean corrosion out of same - which was pretty common. That's a user failure not a part failure, though. BMWs and Nissans with the bulb check circuitry, despite systems from different makers and different countries, do the same thing.
No, the Jag digital dash's main mode of failure was that one, more, or
all of the displays would randomly shut off. Sometimes they wouldn't come back. Finding an XJ40 with that dash that still works 100% is
exceedingly rare.
Then again, finding an 88-89 XJ40 that still works period is rare, so I suppose that's not surprising.
As for the XJ-S dashboard, the comedy vertical scale instruments were, IIRC, totally bespoke and made first by Smiths and then by Veglia. They're not bad in terms of reliability, but man are they ugly and hard to read.
