I need to replace a burnt-out driver's side halogen bulb in my '86 300E. Seems pretty straight-forward; take off the access cover, remove the plug, twist the locking ring CCW and remove the bulb, right? Well, how come I can't get the locking ring to move more than about 5mm? The ABS unit prevents me from getting a real good grip, but still, it shouldn't be that hard to get off, should it? It feels like it's bumping up against a solid stop. Am I missing something here?

Help!

Gary