Just bought a 1991 300E I have a few Questions - PeachParts Mercedes-Benz Forum

ptm6295 · #1 11-26-2006, 05:35 PM

Hi everyone, I just bought a 1991 300E and am very impressed and happy so far. The car is black with black leather, 159,000 miles, and all service records going back to day one. It was a one owner car. Anyway, here is my question:
The defroster vents on top of the dash are always open, even when the climate control system is off. The faster I drive the more fresh air comes in through those vents. Do you think the actuator needs to be replaced, or is this a normal thing in this car? If the actuator has to be replaced, how hard is it to get at, and how do you do it?
Aside from this small problem, the car is great!

Ron in SC · #2 11-26-2006, 06:00 PM

Quote:

Do you think the actuator needs to be replaced, or is this a normal thing in this car? If the actuator has to be replaced, how hard is it to get at, and how do you do it

Most probably, not normal, default when actuator is leaking is for it to stay open.

It is labor intensive to replace, dash must come off.

See link: Actuator in photo that circled is the one for the defrost vent.

http://www.peachparts.com/shopforum/attachments/tech-help/35232d1155165524-no-air-center-evapdone-003.jpg

ptm6295 · #3 11-26-2006, 08:27 PM

Thanks for the reply, i read somewhere that you can get to the defrost actuator from behind the glovebox? I guess that was misinformation.

Ron in SC · #4 11-27-2006, 06:27 AM

Quote:

defrost actuator from behind the glovebox

I might be mistaken. Maybe the defrost is the one acessible when the glovebox or airbag unit is removed. That top element may be for the center vent.

Hopefully someone else will know for sure.

Edited:

See diagram below. If diverter flap element, one I circled in picture in the link above, is leaking I think all air will go to defrost and not to center vent. Still not sure whether changing defrost element will cure your problem. Hopefully someone else will know for sure.

david s poole · #5 11-27-2006, 09:28 AM

this can be done without removing the dash but you will need small hands and lots of patience.[by the way there are two diaphrams for fresh air one on each side with linkage to join].

ptm6295 · #6 11-27-2006, 03:55 PM

Where are the fresh air diaphrams located? Are they easy to get to, or do you have to pull the entire dash? Is there a way to troubleshoot this problem, before ripping the dash apart? Thanks