When I purchased my 2004 XJR I noticed the xenon lights would flicker off when I hit a bump. I swapped out the column control with a used part and this seemed to cure the problem.

I run the car as a toy so in practice it is the type of fault I do not drive the care regularly enough to notice.

Today when driving at night the headlights seemed to flicker on and off once or twice when I hit a bump / dip in the road.

Is this likely to be a fault with the earth or any other bright light ideas?

 

Could be an earth-point somewhere up front, earth points are a known issue to check.

I had the intermittent flickering headlight problem for 4yrs, usually associated with using the indicator. (but sometimes anyway).
(before I managed to get up from my chair)

So given the price of a new stalk, I took the risk and bought used from UK. Problem solved for 6 months and counting.

If you bought a used stalk it could also be faulty and still the known problem. Life is risky, 2nd-hand parts dealers more so.

 

Had that too on 2003 xj8
Ground studs cleaned and connector rings sandpaper cleaned , dialectic grease and tightenend slightly. New hid D1s lightbulbs fitted.

then after a month one of the headlights turned of completely. Ordered new ballast Lad5g or gl 12 pin for early cars with headlight height regulator. And 4 ride height sensors
4 pin without headlight height regulator and just 3 ride height sensors
loosen front bumper put it on the floor and exchange ballast on the bottom of each headlight exchange all other bulbs while at it an try cleaning the inside with a cotton cloth and a long pincher withe some alcool

 

My right 2004 XJR headlight flickers occasionally.
I might try one like this.
No leveling control but at least it has the 12 pin so you don't have to fiddle with the wiring plugs. The amazon reviews are funny in that the Cayenne owners are so happy to have working headlights (under $50 instead of dealership $500) that they do not care if there is no leveling.
How long might i expect it to last? Anyone know? Anyone's guess , right?
To the OP, some say you can just to remove the grill, undo the bumper clips on the radiator support and pop the clips from the fenders. Leave all else connected and pull the bumper forward enough to gain access for headlight removal.
Also, there are these types still available .
https://www.ebay.com/itm/23453744802...mis&media=COPY