Changed! I had to do the work in daylight, of course, so don't know how these Morimoto XB HID will look at night just yet. From the first looks, I can say, though, that I am glad I got the 4500K color - the 5500K or 6500K would have been
far too blue, I think.
After changing one bulb (the now dead one - purple faded to black.

), it definitely looked brighter and whiter than the other old working one on the passenger side.
After changing both bulbs, they look pretty even (in daylight, of course), so will report more on this later.
Luckily as mentioned earlier by SL33P3RM45, I did
not have to go through the wheel well as the Service Manual instructions stated. Whew!!
So, for access (to the low-beam anyway - didn't do the high beams this time) on a Y34 chassis (2003 and 2004 M45):
- the driver side (the dead one) was reachable barely. I put my hand through an opening farther back above the wheel well area and then reached forward a small bit. That allowed me room to move my fingers and do the work.
- the passenger side needed me to remove the battery. This was a pain, since I had earlier rounded off one of the bolts that goes on the battery tie-down. Couldn't find my darn metric wrenches ...
Also, unfortunately, the driver side was a bit too inaccessible to take pictures, so cannot show you how it went. Would have taken pictures when doing the passenger side, but by that time, my hands were pretty grungy and I didn't want to touch my phone!
So, only a brief description here:
- Turn the back seal cap that protects the light electronics - this is a large plastic cap (about 2.5" to 3" in diameter) that rotates just about a quarter turn and then comes off. Remember to be careful when putting it back later so that the rubber o-ring/gasket does not break. My caps were clean so I decided not to mess around cleaning them further.
- Remove the ballast by turning it till it "unclicks". Before pulling it off, try turning it back and forth to see how it clicks in place so that you know how to put it back - the connector has two slots that mount on tabs on the bulb base.
- Then squeeze together and unclip two metal hooks (single wire spring) that retains the bulb base - you can see which way they would need to go.
- This wire spring is hinged at the top, so has to be lifted by the hooks all the way up (needs other hand done from the front of the car) to pull the bulb straight back (you do NOT want to break it inside the lens assembly! Not surprisingly, the OEM was the Philips bulb that Larz mentioned.
- The bulb has a side wire assembly that goes on the "bottom" when replacing. The bulb base has a notch that fits into a corresponding tab on the top of the lens assembly opening.
- Clean the bulb with alcohol (no fingers touching the bulb - particular with the dirty hands from removing the seal cap!!) and slide it in carefully to avoid breaking it!
- Make sure the base is properly positioned (tab in slot - without rotating anymore), squeeze the spring wire connectors and hook them back onto the connector assembly.
- Re-attach the ballast, push onto the bulb base and turn till it clicks (you learned the feel earlier, right?).
- Put the back seal cap on - turning it a bit so that a tab goes into the wide opening of the lens assembly. Then, push the cap in (quite a bit), rotate it a quarter turn till it locks in place.
You are then done! Turn on the lights and see how they look.
By the way,
after I removed the dead bulb, it cracked and a piece of glass fell off ...

I am glad that had not happened inside the lens assembly or while I was taking it out. Would have been a total pain to deal with!
Z