Citroen XM Forum

Probably but Ive never dismantled one...

Any further news on this? I could do with those headlight diffusers sooner rather than later.

Happy to buy a pair of headlights if that will get me the things quicker.

Diffusers are handed beam deflectors.
Fit them the wrong way round and you get a LHD beam.

The headlamp glass lenses have a completely different pattern for lhd John and when I adjusted my German car that is the only thing I changed.
Regards,
Matthew T.

Hi Matthew

I would put money on your LHD glass not being original but retrofitted Mk2 LH glass.
My research suggests that all Mk1 headlamp glass was identically patterned for both RH and LH headlights.
Only the diffuser altered the beam angle and this could be done by reversing the diffuser.
With the Mk2 LHD headlight the diffuser pattern was moved into the lamp glass and incorporated with the original glass pattern.
This required new handed glass moulds to be produced but Citroen only did so for LHD XM's.
One can only speculate on the reason for that, there are a few options.
This was the first headlamp of this type that Valeo produced for Citroen without a diffuser.
So it might have been a trial and for cost or other reasons restricted to a single set of moulds.
The diffuser plastic spec was changed in late 1996, reason not known and these do not yellow with use and age.
Either way the later RHD XM's never got "all in" headlight glass but Citroen used handed glass for the following models.
As it happens I have been comparing RHD and LHD headlight today for a Mk1 Saxo.
A French neighbour has to MOT his LHD car for continued UK use.

John

If there really is no difference between S1 left and right-hand headlight glasses John and that is all I changed, I now wonder how the car passed the MOT, unless I did remove and refit/replace the diffusers??!! The German car has had a replacement nosecone, so you might well be right in your theory about the headlights being later. Am I correct in my understanding that S2 headlights do not then have diffusers at all? With regards, Matthew T.

My apologies for further hi-jacking this thread, but I now attach a photo showing two sets of headlights from my collection with the original Germany car lenses on the right. Please note that the diffusers were removed earlier! Hopefully the difference in the design of the lenses will be clear enough. Regards, Matthew T.

Hi Matthew

Yes, that confirms what I have been saying.
Those are Mk2 LHD glasses that you took from the German car.
There is no pattern difference for the main beams, which is logical.
The only difference to the dipped beams glass is the addition of the pattern on the diffuser.
I will look up my photos of Mk1 LHD headlamps to double check.

John

Once again I am sure you are right John and I note that the photo in the XM coffee table book shows a glass identical to the S1 rhd! All interesting stuff and at least as it turns out I was right to change the lenses in my case!! With regards, Matthew T.

Hi Matthew

Have a look at some ebay items with good descriptive photos.
All new items for early Mk1 (3xLH, 1xRH) and all same supplier.
271066112684, 271046833674, 390520397506 & 390472636650.
Note that all early french XM's should have yellow main bulbs to be as original.

John

Erm, interesting as this is, it's not helping me to get some useable headlights.