Side Marker Lights

Mine is E320 2003 model and I have a manual that says that the catch is on the front and that I should slide the yellow plastic cover towards the front to release the whole lamp holder. I used a smaller flat screw driver and pry open one side (towards the rear) and then used another screw driver to pry the middle part out. I was successful in not scratching the paint. From that point onwards changing the light bulb is a cinch. Try not to leave oil trace on the new light bulb when you put that in.

I believe I read from elsewhere that your older model may the reverse so be careful when you attempt the procedure above.