Peugeot 207 windscreen constantly foggy

[Med_tech3]

My windscreen is constantly foggy on the inside. If I turn on the air con it clears slightly but makes the car chilly!
I can only assume I have water leaking into the cabin from somewhere and it is increasing the humidity. Are there any known leak points? Blocked drainage?
Any thoughts would be appreciated.
Thanks.

[myglaren]

Try giving it a very thorough clean with methylated spirits. The screen interior will accumulate a greasy film that promotes and holds condensation. A very clean screen will be less liable to this and clear more quickly.
The aircon shouldn't make the car chilly, just dry the incoming air that will then be heated by the heater matrix.
It could be that the drains for the screen are clogged, also the aircon drain clogged.
Also worth checking the cabin (pollen) filter is in good order.

[GiveMeABreak]

You don't have automatic air conditioning - but all you need to do is set the appropriate temperature and ensure the A/C button is switched on - that should provide a mixture of air conditioned air at the temperature you require and will dehumidify the cabin.

[Gibbo2286]

I would be looking for water in the car, under the mats etc. leaking weatherstrips or blocked door drains.

[GiveMeABreak]

If the OP is not really using the A/C as it's too cold, then I would expect a lot of condensation build up in the cabin - especially with the damp air in all this rain and heating / cooling of the cabin. You can try closing the air vents overnight to help prevent damp air getting into the cabin. But really, make sure you use the A/C, set the temp to a comfortable temperature and allow it time to dehumidify the vehicle.

Also do check for water ingress under the door seals or for damp patches anywhere collecting in the footwells.

Use the A/C regularly to get rid of moisture - it doesn't have to be on a low temperature to do this - ultimately, if the blower motor gets too damp, the bearings can start to seize and prevent the blower motor from working.

[myglaren]

A quick and dirty temporary fix is to stuff tights/stockings with cat litter and leave in the car - cat litter is hygroscopic.
Not pretty though.

[Hell Razor5543]

Do what you can to get the inside of the glass (windscreen, side windows, and so on) REALLY clean. Any dirt on the glass acts as a seed point for the condensation.

[Peter.N.]

You haven't got the 'recirculation' button pressed have you? I've done it.

Peter

[GiveMeABreak]

Good point that Richard^. Leave that on too long and you'll soon need waders.

[Med_tech3]

Thank you for your replies. I will check for leaks and check the pollen filter. I never use the recirculation button so that isn't the issue. I will make sure I clean the screen and leave the aircon on too.

[Homer]

Thank you for your replies. I will check for leaks and check the pollen filter. I never use the recirculation button so that isn't the issue. I will make sure I clean the screen and leave the aircon on too.

Check the windscreen drains too. This was mentioned earlier but you may have missed it.

There is usually a channel either side of the screen which leads down to some method of leading the water away. It may be covered with a rubber flap. This gets clogged with leaves etc and the result is water making it inside the cabin which causes condensation. You need to clean out the channel and any ducts it leads to and make sure water drains away freely.

[Sloppysod]

All good advice so far, however, I had a XM that suffered from heavy condensation and damp FRONT carpets, I thought it was the heater matrix, however, further investigation proved that the rear lamp seal was damaged and as my dive was on a slope, car always parked nose down, the water ran from back to front........... the reason I am typing this is, don't expect to find the issue where things fell damp.
Also, with regards to Air-con, you should use it for at least 15 minuets each month just to keep the seals tight and as stated above Air-con is exactly that, air conditioning, and not just a way to make the cabin cooler.

[white exec]

Air-con will always be able to extract moisture, even with the temperature set to high. It always has a dehumidifying action.

On most cars, the chilling radiator in the heater (which also dehumidifies, because condensation forms on it and drains away) comes first, followed by the heater matrix, which is able to heat the air if also required.

Put on 'Recirc', the outside air is almost completely shut off*, and the cabin air is repeatedly recirculated through both chiller and heater matrixes. This is the best setting to remove cabin condensation/moisture, with heater temp set to warm. *Not totally, to avoid stale air.
________________

On a similar tack, it is sometimes possible to produce condensation on the outside of the base of the windscreen, and have to use the wipers to shift it. This can happen if the outside air is humid, and cold AC is turned on to the windscreen. This can chill it enough to produce condensation on the outside, looking very much like the interior misting up!

[Michel]

Replace the pollen filter. Every car I've had, including two 207s with this issue had utterly filthy pollen filters..