Halogen to Xenon Headlamps Conversion

I needed to buy a set of replacement Halogen headlamp units for the car. I came across a pair of complete Xenon headlamp units from a donor Megane RS 250. They were being offered at a very good price. They came complete with the bulbs and ballast for £260. A brand new single halogen headlamp costs around that price.

So for those of you considering upgrading to Xenons, here are some details about installing Xenon version headlamps to a non-Xenon Megane III (X95).

If your thinking about whether this is effected by the new MOT laws from 2012 and whether this will become illegal, the official leaflet on the DFT website http://www.dft.gov.uk/vosa/repositor...3-lighting.pdf states in section 1.7

The Department for Transport considers that after-market systems should be required to meet the same safety standards as that applied in respect of these lamps at vehicle Type Approval. Therefore, in order to pass the MOT test, vehicles fitted with after-market HID systems would also need to be fitted with headlamp cleaning and self-levelling systems.

My setup consists of a retro-fit headlamp washer system which works. I will post details about this mod shortly. I will however be working on retro-fitting an auto levelling system in the near future.

The DFT publication also states that:

Where headlamp levelling or cleaning devices are missing or defective, but there is doubt as to whether they are required, the benefit of the doubt should be given and an advisory notice issued.

This statement opens up a whole new chapter in terms of interpretation. If a tester is testing a car that has OEM projector based HID headlamps and correctly functioning headlamp washers and all the beam patterns and everything are fine, then I dont think they will just fail it because it has no self-levelling system.

Back to the topic, here are a few pics of the xenon version projector based headlamp:







The headlamp units are actually a direct replacement. The exisiting wiring harness and connectors all fit and operate the Xenon headlamps. The only thing different is that the Xenon headlamps have the cornering feature which have an additional connector. As the car doesnt have this feature, I didnt have anything to connect to this, so I simply covered with a rubber insert. In the near future I may attempt to get this working using custom wiring.

There is however one small problem with directly swapping a Halogen with a Xenon version. The UCH in the car is programmed for a standard halagon bulb, and after a little while the car detects a problem with the discharge bulbs and will begin to flicker. The reason for this is that the car is sensing a steady current. A ballasts needs are anything but steady. To resolve this I basically added an inline HID anti-flicker decoder to each headlamp unit. It is basicaly a smoothing capacitor in parallel with an inductor. There may however be a way to have the UCH re-programmed to accept HID. The inline decoder works fine for me. If you are going to do this, I would recommend using some weatherproof connectors like the 2-way superseals, and also just as a precaution add a inline fuse. This way, if the decoder ever fails, you can simply remove and replace with another one.

***UPDATE with Complete Photos***