Regular intermittent windscreen misting

[Person]

Hello all, I hope someone can help.
Since yesterday I have noticed the windscreen misting up intermittently - de-mist clears it fine but then perhaps a few minutes after switching this off the windscreen starts to mist up again, this happens gradually over a few minutes and then disappears (without using de-mist), a few minutes later it starts to mist gradually again (but never enough to completely obscure the view) then clears - and so on! Strangely this happens mostly on the driver's side, but can happen on both. Coming back to the car after parking for 30 mins or so and the windscreen is misted badly.
What is going on??! AC is working fine.
I've read about a possible faulty evaporator sensor - the AC pipes after stopping are very cold but not iced so I'm not sure if that rules that out?
V puzzling, any help very gratefully received.
Tom

[LizardOfBodom]

Start with more obvious possibilities, maybe the cabin filter is old/damp? When was it last changed?
Is there any signs of leaks under the floorcarpet?

[Person]

I'll check the cabin filter - but looking on-line it looks like a complete mare to get to! Would it account for the misting coming and going regularly - and more often than not on the driver's side?

[LizardOfBodom]

Originally Posted by Person

I'll check the cabin filter - but looking on-line it looks like a complete mare to get to! Would it account for the misting coming and going regularly - and more often than not on the driver's side?

Yes, done this "pleasure" myself 2 months ago. Doable, but not funny at all.
And yes - that would defo account for misting especially if filter is old and damp, causing the air not recirculating properly.
Also just make sure there is no water anywhere in footwell area - like pull out carpets, not just mats, to see if you dont have any leaks. Unfortunately it happens to some, especially if car have sunroof or there is heater leak.
But cabin filter would be my main culprit. if you dont know when it was lastly done - get yourself one, pretty cheap, as once you get to inspect it you will want to replace it anyway not to go trough this acrobatic experience again

[Bigchewie]

I replaced the cabin filter recently with a Mahle one, it wasnt as flexible as the OE that was removed, I would recommend removing the fusebox bracket as well as dropping the fusebox, be careful not to drop the nuts, I dropped one, still to recover it, but will get it eventually

[LizardOfBodom]

Originally Posted by Bigchewie

I replaced the cabin filter recently with a Mahle one, it wasnt as flexible as the OE that was removed, I would recommend removing the fusebox bracket as well as dropping the fusebox, be careful not to drop the nuts, I dropped one, still to recover it, but will get it eventually

+1 to disconnecting CEM, much easier that way. I would disconnect battery when doing it, just in case, then spray contact spray on connectors when reconnecting CEM.

[Person]

Many thanks all. Have ordered a replacement and will tackle this later in the week. Perhaps after a stiff drink. Fingers crossed this fixes the issue - will report back...

[Person]

Quickie - is the radio going to ask for a code if I disconnect the battery?

[LizardOfBodom]

Originally Posted by Person

Quickie - is the radio going to ask for a code if I disconnect the battery?

Nope.
Coded to individual car, no worries with battery.

[Person]

Right, just did this. It really is a pig of a job but amazingly my knuckles have come out unscathed. What an awful design.
Anyway, the filter that came out was pretty clean actually, so I reckon it must have been changed recently BUT the lower half of it was sopping wet. So, I have a leak somewhere. Any ideas where to start looking?