[Guest (MBNZ)]

Hello,<br>
I have an '85 300D turbo with 258K miles on it. A few months ago my center two a/c vents catastrphically failed (they didn't gradual buld up to it or anything). I'm pretty sure I didn't do anything to them to make them do this, I mean when I drove back from Austin earlier that day they were fine but then that evening they were sealed shut! So, being as that it was not a gradual failure I think it is something electrical, unless a diaphram suddenly ruptured in the valve. Has anybody had this problem before? I've seen this question asked before, but never an answer given. I was thinking about rebuilding the climate control amplifier in the same way that the cruise control amps can be rebuilt (you know, resolder every joint), but would like any input that y'all can offer. Thanks in advance,<br>
-Rob

 

[Guest (MBNZ)]

i dont think i can help but,<br> <br> because its a later model i assume that u have buttons to controll where air is vented, instead of a sliding switch on the dash.<br> <br> it could be that, maybe, the buttons have failed and it is set to a mid way point between off and on?<br> <br> im intrested to hear what it actually is, im sure someone here would be able to hep out. if not it woud be of great benafit to us all, if u do take it in, to post what the problem is and how much it is to fix.<br> <br> louis

 

[Guest (MBNZ)]

Hello,<br>
Yes, i do have the buttons to control the airflow, but regardless of which button I push, no air ever comes out the center two vents. I'm going to try and fix it myself once I get my climate control manual in later on. I'll let you know what happens, but would still appreciate any input anyone else may have.<br>
Thanks,<br>
Rob

 

[Guest (MBNZ)]

Hello,<br>
Yes, i do have the buttons to control the airflow, but regardless of which button I push, no air ever comes out the center two vents. I'm going to try and fix it myself once I get my climate control manual in later on. I'll let you know what happens, but would still appreciate any input anyone else may have.<br>
Thanks,<br>
Rob

 

[Guest (MBNZ)]

Well, I've been looking at it today and I think the actuator is bad. The cost for this part is approximately $30 I'm told. However, If you have someone else do it it will cost a lot in labor because you have to remove the dash to get at it.

 

[Guest (MBNZ)]

Turns out it was the pin that connects the control roc from the actuator to the flap. This part costs about $1 at the dealer, but is all kinds of fun to get to. This job is doable, but make sure you have plenty of time to put your car back together as you will have the dash off.

 

[Guest (MBNZ)]

Rob, I have the same problem with my 85 300td. What exactly needs to be done to fix this problem. Thanks

 

[Guest (MBNZ)]

It took 6 months finally I decided to look into the same problem in my 85 300D. I found just like Rob said it was a pin. What I did was using a solid electric wire about 1 1/2', poked through both holes, and twisted them together without taking dash off. It was hard about 30 mins. You have to have a samll hand and patience because you can only work with one hand, actually only three fingers. Also, the duct and vent has to be rubber duct. I don't know if 83 has rubber duct or plastic duct. You might have fixed problem, this message might be too late for you.

 

[Guest (MBNZ)]

<br> I had the same thing happen and fixed it the same way. Like they said, the job is a bitch but can be done without removing the dash. Take the glove box out, then you can see the vacuum servo is working. Pull back the rubber boot on the center two vents and kinda reach in there and feel around for the flap valve pivot hole. The with one hand using three fingers slide a piece of wire through the hole. I used a brass brad fed in in a hemostat, but a piece of wire sounds better. Twist it off and check operation to make sure your got the wire through all 3 holes. It took my hand a couple a days to recover, but it the A/C works much better now! Isn't DIY fun? The dealer and the local independent shop wouldn't touch the job, leaving me no choice!

 

[Braingears]

A/C Vent

Bruce is right. The vacuum servo is worn-out. Disconnect the servo and leave the flaps open. Don't forget to disconnect the Vacuum line and plug it. Everything will work better.

Also listen for leaks while the car is running. This can help with other vaccuum issues.