lamboda

Hi Guys,

Just got into a 2009 C300 4Matic Sport and I notice there seems to be an issue with the A/C system.
I drive and use my heater with A/C on to dehumidify my car when it's rainy or snowy as try to take moisture out of the interior and windows, such as drying my floormats. However, after when I park my vehicle and return to it, it fogs up my windshields over the course of a few hours. All my windows are fogged from the inside. It's a wet kind of fog as well, where there's slight water droplets near the top inside of the front windshield

However, when I use my heater without A/C turned on, it is able to keep the fog away and when I return to my car after parking, it doesn't build up fog in the inside of the windshields. Additionally, there is a slight smell occasionally (imagine a light fart smell) during use of the heater

Any insights on this ? I feel like it could be a A/C Drain blockage issue, but would love to hear if anyone's got similar problems and have resolved.

optimusprime m1

I would check drain holes and vents are clear .If they get bloked up the blower sends damp air on to the screen ..