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Xenon conversion

36K views 14 replies 14 participants last post by  SADNX 
#1 ·
Being in the final stages of a halogen-to-xenon conversion on my 2003 5-door 2.0 16V, I thought I'd post some info on the progress (and pitfalls) this far, just in case someone should wish to do a similar mod. Let's start.

First, let's see what are the (main) differences between halogen and xenon cars:
- headlights
- xenon "brain" boxes (integrated in the headlights)
- UPC-to-headlights wiring loom (UPC=engine room fuse/relay box)
- dashboard rheostat
- front and rear axle position (height) sensors
- headlight washers

Most of you probably know what the Phase 1 xenon headlights look like on a Mégane, but here's a pic of a "virgin" pair right out of the original Valeo (=the OEM manufacturer) boxes:


And an interesting(?) shot of the inside showing where the D2S-type gas discharge bulb goes, plus the integrated, non-removable beam height adjusting motor. Also visible is the double-row connector socket where the wiring loom from the car connects to:


Another shot from underneath, showing the large rectangular opening where the "brain box" i.e. the combined xenon ballast/beam height adjustment electronics box goes:


In the above picture the D2S xenon bulb has been fitted and there is an aftermarket "cheapo" bulb socket with red and blue wires connected to it. In the rectangular opening, you can also see a small black rectangular connector. This is connected via headlight-internal wiring loom to both the stepper motor and the headlight's external double-row connector described earlier.

I couldn't find the original "brain boxes" for a reasonable price first, so I started the project using generic Chinese HID kit ballast to drive the bulbs. The ballasts would be have to be mounted externally from the headlights, since there wasn't enough room inside. Here's a blanking plate I made of a 3 mm aluminium plate, to seal off the opening where the brain boxes should be:


Here's where I fitted the LH ballast:


...and the RH ballast:


I knew from the beginning this would be a temporary solution, so I only fitted the ballast holders using extra-strong double-sided tape to avoid having to drill any extra holes.

Unfortunately, even after all this, getting the xenons to work isn't a simple matter of plug&pray. Here's why:


Those are the original connectors fitted to the halogen headlights. The bigger one is a single-row plug with five pins (parking, indicator, dipped beam, high beam and earth), the smaller three-pin plug connects to the halogen version's external beam height adjusting motor. And like we remember from earlier up, the xenon headlight only has one connector with two rows and nine pins. So the wiring loom of the halogen car cannot be connected to the xenon headlights. Simple as that.

One solution is to buy a new wiring loom off the xenon version from Renault. The bad news is, its pricing is out of this world: I was quoted 204 euros for it! :rl: No way I was going to pay that much, considering the only differences are three extra wires and different connectors at the end of it.

So I decided to modify my existing halogen wiring loom. Renault (naturally) don't sell those special connectors separately, so I had to source them somewhere else. Luckily (after over a month's research) I found a tip on a German Opel Vectra forum. Apparently they had the same connector availability problem trying to connect their Valeo xenon headlights (the same manufacturer as the Mégane headlights), but had found a solution for it: a Saab dealership!

So I visited my local Saab garagist and asked if they'd recognise the part number quoted on the German forum: 12788954. As it happens, their system showed it indeed WAS a 10-pin connector with two rows! Even more exciting was that the retail price was a little shy of three euros! Multiply that by two and throw in the required connecting pins, I'd still save a LOT compared to the 204 euros at Renault! Provided the connector would fit, that is....

For six euros, i took a change and ordered a pair of those connectors. The delivery took a few days, after which I could collect the parts:




The connectors used by Renault are black and these are white (and it says "SAAB" on them...) but as long as they fit, who cares! Here's one of the connecting pins that locks inside the socket:


AND HA-HAAA!!!! :rockon: THEY FIT!!!! :dj:

Next job was to remove the front wiring loom from the car so I could do the modification cleanly and professionally (before finding the right connectors, I'd just bodged the connection to the headlights using separate 2.8 mm spade connectors, shrink tubing and great untidy looking blobs of silicone mastic to keep water out of the connector recess).

Removing the loom from the car was the usual bumber off, headlights off routine, then unplugging all the relevant connectors (headlights, windscreen/headlight washer pumps, horn, foglights). Naturally disconnected the battery first and in fact lifted the whole battery out of the car for clearance. Then popped off the UPC cover to find this sight:


There you can see the two connectors I've pointed out. Disconnect them, and off comes the front wiring loom! In this modification the connector 'R9' is what interests us. The xenon brain boxes need three extra wires compared to halogens:
1) speed signal, so the brain knows to lift the aim by 0,3% when the speed exceeds 30 km/h
2) height signal from the axle sensors, so the brain knows to adjust the beam according to whether the nose is pointing down or up
3) diagnostic line, so the brain boxes can be correctly configured through the OBD2 socket in the centre console, by plugging ín the Renault CLIP diagnostic computer.

Now, running three extra wires from headlights to the UPC isn't a problem, but if I had to run the corresponding wires from the 'R9' all the way to the individual components (ABS/ESP unit for speed signal, centre console for diagnostic socket and then the front and rear axles for the height signal) then that would be a bigger pain in the derriere... Fortunately during wheel changes I had seen an idle connector at the front suspension, so I was somewhat hopeful my car might be prewired already from the factory. And:


..seems like it was!!! The wire colours and places in the connector (pins 2, 3 and 4) matched the original wiring diagram for the xenon version from Renault! So a massive phewww.... there!

Then I moved to the worktable and started redoing the loom:


In that picture I've already replaced the two separate connectors at each end with the new connectors from Saab. The untidy mess are the three extra wires I needed to add. Here I've already fitted them to the farthest (=RHS) connector. Next I started undoing the original electrical tape wrapping. That revealed all the individual wires. I then identified the three wires used by the original halogen beam adjustment motors (black, green and violet). These would no longer be needed, so I completely removed those from the loom. Next i straightened the three new wires (orange, salmon and grey) and routed them along the rest of the wires. Then it was just a matter of rewrapping the wires in new electrical PVC tape, followed by canvas tape in appropriate places.

A longish story cut short, here's the "new" loom:


And to show that the Saab connectors really do fit, here are three pictures, from a gentle poke to full penetration: :shiny[1]:




And yet another shot from a lttle further back:


And as you can see from the above picture, I've managed to source a pair of (used) control boxes as well:


Those are the brain boxes I've been talking about. They take care of igniting the bulbs with a high-voltage surge (~20,000V), then keeping up the arc with a roughly 85V alternating current. That job is for the smaller connector at the corner of the box and that's where the shielded cable with the bulb socket plugs into. The bigger rectangular connector is where the headlight's inner wiring loom connects to, and this takes care of the following: five pins are "outgoing" to the beam adjuster stepper motor, the rest are "incoming" i.e. the speed, height and diagnostic signals plus naturally the + and - feed for the dipped beam.

I'm still missing the axle sensors and the new rheostat (without the thumbwheel) for the dashboard, but I just received an email from Germany today, and those parts should be heading my way on Monday.

Yesterday I fitted the loom and the headlights to the car. All the lights work well, but the beam adjustment is yet "dead". Today I took the car to my local Renault garage to have the car configured for xenons and have them initialised: What a waste of time and money! They had absolutely no idea of the whole thing, they couldn't even find the configuration menu from their computer! :dazed002: Having had unfounded faith in their abilities, I hadn't bothered to print out the necessary pages from the Renault manual describing the procedure.

According to from what I've been studying from the original Renault workshop manual, the height signal from the manual thumbwheel should be in the same voltage range as that from the proper axle sensors, so from the control boxes' point of view it shouldn't matter if the height is controlled manually from the thumbwheel or constantly varying from the axle sensors. Even if I for the moment only have the manual adjuster it would have been nice to at least have the car "taught" it has xenon, but thanks to the completely unable garage that may now wat until I've calmed down and fitted the axle sensors as well. Then I'll pay them a new visit, this time with the necessary documents to teach them by hand if nothing else helps. Only wish I had the CLIP tester at home, but at 1500 euros that's a bit steep for a private person....


Anyway, that's the progress so far, hope you didn't fall asleep and hope there were enough many pictures in this post! :smartass:
 
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