This is a great write up on this! Thanks for posting. Nice find on the lens too.. I think the lens is available in Europe but not in the US due to DOT restrictions.. I learned that when I replaced the lenses on my BMW. Did you get that error code in the display on the dash?

 

Would you believe I owned the car for almost a year and never knew it has stepper motors to adjust the headlight aiming? It was when I hooked up a DAS diagnostic system that I saw "F" for the lights. Displayed the fault codes and "bad cable/connector" and "stuck motor" displayed. (I'm thinking to myself, "Headlight adjuster motors?")

I was replacing the lens so I figured I'd correct the stepper motor issue. After the above work I cleared the error codes and used the DAS to run both stepper motors to max and min positions then programmed it to "auto". Kinda cool to make the headlights' beams shift up and down with the click of a mouse button!

The headlights are Xenon on a 1999 pre-facelift W210.

 

I wouldn't use WD40 on electrical connections unless you are talking about the WD-40 300083 Specialist Electrical Contact Cleaner Spray... Contact cleaner comes in lubricating and non-lubricating formulations. Sounds like you want the lubricating type.

 

Update

Replaced the other lens today.

First photo is a better photo of the headlight adjustment stepper motor.

The other photos will give you an idea of what a box containing a replacement headlight lens looks like after arriving from Latvia...it did not feel the love coming this way. Lens arrived with minor, but repairable, damage. Internal lens had two of the four mounting points broken, repaired with silicon seal rather than trying to send this one back and hope for another to arrive in better shape.

This time it took less than two hours.

 

If anyone needs replacement xenon lenses I have a set for prefacelift cars.

 

If you have a good set of lenses, advertise them on Ebay. That is where I buy quite a few of my parts.

I paid $125 delivered for a lens from a private individual who hand-carried it back from Germany and I paid $196 for the other lens delivered from a commercial enterprise in Latvia. $321 total for two lenses versus $1350 for Hella replacement assemblies. Both lenses were new stock, not salvage. Salvage lenses are significantly less valuable. Plastic is great for style but sucks for durability.

FWIW.

 

Update for manual adjust of headlight

Full disassembly of the stepper motor assembly.

Left headlight threw another error code. I decided to pull the headlight and fully disassemble the stepper motor assembly. Disregard the first two slides, I like to document all of my work for future reference.

 

Update: stepper motor refurb

Left headlight stopped adjusting. Attached is the diagnosis and repair of the stepper motor issue. At some point in the future I will remove the headlights again and rewire everything but the Xenon headlight harness. The insulation is becoming very frangible.