PAUL WAGER
We turn our attention to the flickering HIDs
REGULAR READERS will remember that last issue’s report centred around the priorities of making the door locks work properly and stemming the water leak into the boot courtesy of a replacement rear lamp.
A month on, I can report that the locks are still working perfectly and the boot appears finally to be dry, meaning I can turn my attention to less pressing matters like the flickering headlights. This has been an ongoing issue for a couple of years now and various solutions have been tried but none seems to have effected a full cure.
It’s a common issue on X350-generation XJs fitted with the HID lamps and the consensus among owners is that it’s generally caused either by corrosion in the various connectors or by a failing ballast unit – the module which provides the high voltage to drive the bulbs (or ignitors as they’re properly known) in an HID system.
I’d already cleaned up the headlight earthing points and the multi-plug from the wiring loom to the lamp units and although this appeared to have improved matters, it still hadn’t cured the problem, meaning that I’d need to inspect the connectors at the ballast units.
Rather unhelpfully, these are located on the underside of the lamps, meaning that the assembly has to be removed to gain access – which in turn means the bumper cover needs to come off.
Or at least, that’s what the various forums will tell you, but as I’ve discovered it’s possible to ease one corner of the bumper cover off sufficiently to provide access to the lower mounting bolts of the lamp unit. It’s really a two-person job to remove and replace the complete bumper skin without paintwork damage, but doing it this way makes it a quick and easy job.
Having studied the lamps in operation and swapping the bulbs from side to side, I was also fairly confident that it was only the offside which was flickering, so this was the one I set to work on.
As I discovered, this is one of those jobs which at first sight might appear daunting but is actually really very simple. After removing the Torx bolt inside the wheelarch to release the plastic arch liner, then the five bolts holding the engine undertray to the bottom edge of the bumper skin, it can be released from the clips at the wing using nothing more than fingers. The front grille can then be unclipped and slid out of the way, then after the two plastic lugs by the headlamps are released, the bumper cover can be eased forwards sufficiently to allow the lamp unit to be unbolted and wiggled free.
With the lamp out of the car and disconnected from the main loom, the ballast could be unscrewed and it was immediately obvious that the connectors were pretty crusty with corrosion. A quick squirt of
