Recently I dove into a DIY project that initially seemed too complicated. If you’re a fan of the Wheels posts you might remember I purchased clear projector lenses to install on my BMW E46 M3. When I realized the ZKW-R lens installation required me to take my HID Xenon headlights completely apart I wondered if it was worth the trouble.
I went forward with it because I wanted to inspect the inside of the passenger-side headlight. When I replaced the HID bulb I noticed that the inside assembly was loose, it was not sitting solidly inside the outer container. The headlight worked fine but this bothered me. Unlike my E39 M5 headlights, on the E46 the outer plastic lenses simply clip off. So I removed the headlight from the car to take a closer look.
You can guess what happened at that point. The headlight was out of the car and I had taken the cover off – why not give the ZKW-R project a try? I still would have held off if it wasn’t for an excellent video from Jake W of E46Fanatics.com that detailed every step. The wisdom of the crowd led the way yet again.
The projector lenses that originally came with my headlights were deliberately a bit foggy by design. It seems strange in the current era of LED and laser lighting, but back when HID lights were new technology there was concern about blinding oncoming drivers since HID was so much brighter than halogen reflector lights. The slight frosting of the lens and the line straight across the middle were meant to decrease brightness and blur the cut-off line slightly.
The ZKW-R lenses are crystal clear. But getting to the point where you can replace the lenses is involved. Obviously you need to remove the entire assembly from the car, which is not as easy as on the E39 M5. Removing four screws, unplugging some wires and having some patience are required.
The ballast (ignitor) unit cannot be disconnected from the driver-side headlight. It has to come out as well. This inconvenience isn’t always mentioned in online DIY instructions:
Taking the outer plastic cover off is easy; it just requires undoing seven clips along the edge of the headlight assembly. Then you need to turn the two adjustment screws to move the inner assembly further out and down.
At that point you can disconnect the two adjustment brackets that hold the inner assembly in place. On my passenger-side they were already detached, hence the looseness. Then came the trickiest part of the surgery – reaching in from the back and popping off the leveling arm from its bracket, the only thing connecting the inner assembly at this point:
Now you’re getting close. Three screws separate the lens from the reflective bowl and bulb:
Once you have access, fold back the tabs, remove the metal clip holding the lens in place, and swap out. Some owners reported bending back the metal piece marked RV in the image above to improve light and cutoff further. I didn’t want to go there and damage the shutter somehow.
Once the lenses are swapped you slowly work backwards to put everything back together. Reattaching the adjusters solved the original wobbly inner assembly on the passenger side. I also replaced the rubber gaskets that clip to the top of each headlight to keep water out because they had degraded over time.
I took a video after I had done the passenger-side headlight. It’s not dramatic but the cutoff and brightness are improved:
From a ROI perspective the ZKW-R project was not the most effective DIY I’ve done on the car. It was a big time investment for an incremental improvement in performance. But I got a lot of DIY satisfaction from tackling something I first thought was above my pay grade.
When I mentioned this job on one of the forums another owner said ‘if you’re going to that much trouble you should have swapped projectors!’ There is always a next step when you’ve got the BMW DIY bug. Maybe next year!