i have a 2002 s40 1.9t almost 100k miles. I have always had a problem with it in the winter and colder months. It always fogs up. When i start my car up in the morning to get the ice off anf am fog ill leave it running for a few min with the defrost on high and hottest. I get back at my whole car is fogged up including the rear view mirror. after this it really never came off my entire car ride (about 40 min).... also i drove to the mountains the other week and my car started to defrost on the highway. i put the defrost on it helps but my car really never defrosted completely and i had to keep it running the entire time or it would fog up again. if i changed the dial from like 2 to 1.5 it would start to fog up. any1 have this probelm as well.
Thanks

 

Are you 'recirculating' the heat or are you keeping the outside air on? Recirculating the heat will not rid the auto of the moisture but the cold outside air introduced into the heat will help. You can also keep your air conditioning on. Do the floor mats of your Volvo have a lot of water in them? You see, hot air in an auto with a lot of moisture in it will cause your glass to fog up in the winter.

r.

 

do you even get any heat???

 

when it is in defrost you can't recirculate the air and the ac in on (light). It heats thats not the probelm i get hot so i turn it down then the fog attacks.

 

You may have a heater core problem.

 

I agree thats what usually causes the windsheild to fog.

 

Is there a 'sweet' smell inside the Volvo? Is there an oily 'film' on the wind screen/windows? What TECH is suggesting is that your heater core is leaking which if it is will cause fogging and the above mentioned issues.

r.

 

i wouldn't say there is a smell or any oily film in my car

 

I would still double-check to see if the climate control is in "REC" mode. On most cars the REC has separate control, regardless of whether the A/C is on or not. However, I have never driven an S40 so I could be wrong.

Try going over the owner's manual for "REC" and "VENT(fresh outside air)" mode control functions. If the heater core is fine, then the only possibility left is the ventilation mode problem. If controlled electronically, either the climate control module or the damper motor (if so equipped) may be shot. If manually controlled, there may be a breakage somewherein the linkage/cable.


JPN

 

You guys remember the drain under the condenser in the 240's? It drained water from condensation when you ran the A/C on a humid day? (that pool of water under your car) Does the S40 have the same thing? Could it clog and leave moisture still inside the car? Just a WAG.