My 95 C280 was bought used from MBZ dealer, and all was fine except this strange smell from the vents. The smell goes away if I have the a/c or the heater on. If I have the climate control on EC for regular ventilation, it starts to smell like ammonia (my wife thinks smells like vinegar). Any ideas? Should I change the dust/pollen filter and/or do the lysol magic from the fresh air intake? Your help would be greatly appreciated.

MOST all makes of cars have this problem. Spraying a lysol type of product into air vents might help. There was a service bulletin from MB on this subject.

A friend of mine have the same
problem on his Saab.One detailer
told him to spray Ozium on the
fresh air intake bellow the
windshield outside the car,
and it works.

Hope this help.
Clauser1

I have used "Ozium" for the same problem on various cars. What has worked for me is to turn the car on, open all of the windows and sunroof, turn on the blower, open all vents, then spray a few good blasts of "Ozium" into the fresh air intake below the windshield. Do this a few times and let the fan run a few minutes. Let it air out for a bit and everything should be OK. It may take a few treatments to make it disappear completely. You may also want to investigate changing the dust/pollen filters. Good luck!