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Steam coming from vents

Hi, I have a 2007 Mercedes B Class. I've had a damp problem for a while but can find no evidence of leaks and have checked all the window seals, all appear fine. It takes ages to demist the windscreen and cold air works best. Sometimes I have to drive with the windows open to keep the windscreen clear! The other day was frosty and when I turned on the air (don't have AC) steam came out of all the vents. Any idea what is causing this and how to fix it, its going in for service D shortly? Many thanks, Breda

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  • Mercedes-Benz Master
  • 1,205 Answers

Sounds like a faulty heater core. Does it smell like rotten apples or anything like that? If so its coolant

Posted on May 17, 2017


6 Suggested Answers

  • 2 Answers

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Posted on Jan 02, 2017

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SOURCE: air not coming out of vents

what your problem is that you have a issue with the vacume system, what i did was removed the bottom panel on the passenger side looked up and you will see a bunch of wires, look for a black box (should be right above your head by time you squeeze in there and it has a yellow/amberish type of color you will see that you can remove this its a rubber piece cut the pink tube on the side about 2 inches away from the plug assembly, and slide it into the blue tube this will bypass all controlls and shoot the air out of the front vents, you WILL NOT beable to set it to defrost max/normal or htr (mainly which vent flaps are where) this has worked formonths and the a/c acts as if its on normal mode to use the heat just slide the switch :) until you can test all the other equip this will keep you cool or warm

Posted on Jul 24, 2008

SOURCE: 2005 Dodge Grand Caravan

99% chance it is the blower resister located behind glove box. Squeeze glove box in and pull out.
The resistor is right behind it, dealer part cost less then $20.
Dodge has had this problem for over ten years and until recently did nothing. Now they combine fuse with resistor, suppose that will correct it?

Posted on Oct 13, 2008

SOURCE: a/c vent issue

heater blowing cold when engine idleing,works good when rpm are up. what is problem? pete

Posted on Oct 24, 2008

  • 1 Answer

SOURCE: Subaru Forester window air leak

take out the tweeder covers if you have tweeders or remove the triangle covers were the tweeders woud be ,then stuff a klittle foam in their,worked for me

Posted on Mar 14, 2009

SOURCE: 2001 buick lesabre-ac problems

  • Assumed your AC unit is OK, but uneven temperature distribution. Try to throw the heater on an off severtime. A sticky valve on the heater would cause similar problem.
  • Observe the RPM while parking your car. While the AC cut in cut out (or turn on an off). If it cause no load on the engine. The freon may be low or the compressor is bad. In this case only the intake side of the evaporator is cooler than the other side.

Posted on Jun 04, 2009

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Hi breda
your car problem is that, the heater matrix is leaking inside the car.
it cause the coolant level to go down. Probably you have noticed that your car loosing coolant.
good luck

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