Some months ago, the rain-sensing wipers on my 2004 XJR stopped 'sensing'. The auto setting on the wiper stalk basically put the wipers into the fastest (manual) delay wipe mode. The rain sensing wipers sure were convenient, but I figured the much cheaper answer was for me to simply turn them on and off like the old days rather than going to the local dealer for a diagnostic. About the same time, I began to notice that the lights occasionally began to flicker. Initially I only noticed it at dusk/dawn and I figured that the system just couldn't figure out whether they should be on or off. It's now done it a couple of times in both very dark and very light (only noticed because the touch-screen display in the dash was flickering between day and night mode) conditions.
Any chance that both auto functions are controlled by a single controller unit that may be going out?

 

You have a 2004 XjR, which is not a 1995-1997 Xj6 (X300). Try posting in the X350 section.