Windscreen demist blowing on one side only?
07-07-2018, 02:53 AM
#1
Windscreen demist blowing on one side only?
Hi. When selecting windscreen demist on my ‘03 E500 (right hand drive), I get lots of air blowing out of the demist vents on the left hand side of the screen, but none at all out of the other side (where I sit...). The rest of the air-con system seems to work ok. It’s winter here in New Zealand, and I really would like to have a fully functioning windscreen demist system. Any suggestions as to what may be causing this and what I can do to fix it will be most gratefully accepted, thank you.
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age911 (07-09-2018)
07-09-2018, 02:46 AM
#3
Thanks Plutoe. I am an aircraft engineer by trade, and am happy to tackle most jobs on the car by myself, but of course I dont have access to specialist MB tools or test equipment. With that in mind, is this something that is relatively straightforward? If it is, how do I replace the faulty actuator? Thanks again.
07-09-2018, 01:20 PM
#4
Out Of Control!!
As you know all forums are loaded with suppositions and misinformation and like you, I doubt you would change out an engine without preforming some basic diagnostics---that's my suggestion here, before you start ripping the dash apart to get to the flap actuators, find someone with factory diagnostics and confirm the problem.
07-12-2018, 02:49 AM
#5
Wise advice thank you Plutoe. The diagnostic tool has recorded a B31 (C-AAC multifunction sensor) fault, and an M2/9 right defroster flap actuator (mechanical fault). I don't know what the multifunction sensor fault might be, or if it is still even an issue. The defroster flap actuator is clearly still an issue though. I see elsewhere in the forum that actuator levers are prone to failure, so that could be the problem. My next question then is, any suggestions as to how to access the actuator? My car is right-hand drive, but I'm guessing this actuator is in the same place, regardless of which side the steering wheel is. If I have to take the dash apart to get to it I will, but would prefer an alternative method if there is one. Any suggestions most welcome :-)
07-20-2018, 08:15 PM
#6
Right hand side demist flap actuator
An update and potential info for any other right-hand-drive W211 owners who are having a similar problem. I removed the dash so as I could access the flap actuators. This was surprisingly straightforward thanks to the excellent instructions on the Pelican Parts website. Once that was off I could see what I think is the suspect actuator, but unfortunately it's not easily removable; two of the three screws that attach it to the housing are very difficult to access, because of the proximity of a part of the underlying dash structure. I've attached a picture to show what I mean. To gain access to the screws I would need to move the housing somehow, and I've decided not to do until I have plenty of time on my hands. I did notice that I could push the flap controlled by the actuator a very small amount, and subsequent to that the actuator seems to be working as it should. Perhaps moving the flap realigned some internal switches or something. I'm not confident that the original fault won't re-appear, but in the meantime will enjoy my demist / defog while it is going properly!
Last edited by age911; 07-20-2018 at 08:17 PM. Reason: spelling error
