gsr,

How do you take the vents on the dash out, without causing any damage. I am in the process of replacing my dashboard, and I do not break anything.

Thanks a lot,

Sam

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1989 300E, 152k miles
1988 300E, 172k miles


"There is nothing more expensive than a cheap Mercedes-Benz" -unknown

There are four little metal spring clips that hold the vents in place. You gently pry up with a tiny screwdriver while wiggling the vent forward. It comes out a little bit at a time. The center vents also have a screw on one (or both?) sides, but I think the end vents just use the clips. They're a little annoying to remove. If you have to use force, you're probably doing something wrong - they should come out fairly easy.

BTW - if you are pulling the dash to replace it, it would be foolish to NOT replace all the vacuum pods - I assume you plan to do that while it's apart!

I posted earlier in this post about the possibility of vacuum loss from the climate system effecting engine operations (thank you GSXR) and noted that my climate system worked properly but I was mistaken when I had to turn on the windshield defroster yesterday and got only hot, real hot defrost and I cannot seem to change it that much, even with the control nob turned to coldest.

You can hear the AC comp. come on and it does try to cool it down a bit but something is telling the heat to engage at full open.

Does anyone know what's up with my defrost? All other functions seem to be normal!

gsxr

Thank you very much. I will read your post, and see about the pods.

Thanks again.

Sam

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1989 300E, 152k miles
1988 300E, 172k miles


"There is nothing more expensive than a cheap Mercedes-Benz" -unknown

Sooty - sounds like the monovalve is stuck on, or not getting the signal to turn the heat flow off? Might be hard to diagnose on a 124... this is not a common problem like it is on the 123 (which has a *totally* different monovalve setup). Could also be a bad pushbutton unit.

Sam - good idea - and good luck!

Yep. It's supposed to blow only hot when the defrost selector is on with the A/C compressor engaged to dry it out. The defrost selector is ment for quickly defrosting the window like when you are just starting up. If you want cold air coming from the defrost vents hit the button next to the defrost selector. This will still vent air through the defrost vents but you can have cold air if the temp selector wheel is on cold setting.

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1987 300TD
1985 300TD (sold)
1980 300TD (sold)
1972 280SE 4.5 (sold)

Thanks for that reply Christophe.

While I do agree with you that heated air is mixed with AC/cold, nothing clears a fogged window faster, but this just began happening!

Before, the defrost used to come on only warm, or set by the thermostat temp setting, not scalding hot, as it is now! You can't use it on a warm day, it'll drive you right out of the car! I doubt MB would have it this way!

I have a couple of things to add here. Replacement of the diverter pod (small black one on top of the heater box) and center vent pod require that you remove the top of the heater box. A magnetic pickup tool is a HUGE help - it's too easy to drop the small metal clips into the console, not to mention the two screws that are up against the firewall (a bit hard to see). The diverter pod is held in place by three press-fit washers, a poor design IMO. Use small diagonal cutters (dikes) or end cutters to get in under the washer and cut the plastic stems. To press the washers back onto the new pod, a small 1/4" drive socket works well.

Removal of the bracket holding the seatbelt warning relay (it's to the left of the left recirc pod) will make removing the pod a million times easier. Removal of the defroster pod makes it easier to remove the right recirc pod too.

Sooty
My '87 300TD has the same defrost you are describing. Hot as hot can be and you are correct in stating it will drive you out of the car. Mine is also showing a mind of its own when it comes to the compressor engaging. Sometimes it will other times it won't. I find the second to be the most annoying. POD replacement will be one of my late Fall's project.

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Steve
'87 300TD - 132K - Soon 4-Sale
'84 300D Turbo - 122K - Driving
'77 VW Type II - 77K - Restored
'08 250EX Ninja
English Bulldog (Brier) - My best friend. Passed away 12/02/04 while in my arms.

As a note to GSXR comments,

I have a friend which went with the $5 diaphram replacements for his W124. He was/is *NOT* happy. They do fit... they do not leak but be warned the travel is not equivlent to the stock units.

If you can afford the OE parts, this is not the place to save money. Too much work !

Thanks for the p/n's . I double checked mine 5 minutes ago. I've got all the correct stuff and have planned out about 8 hrs today. If all goes well, we'll drive it to work tomorrow. If not... wife can take me=)



Michael

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Michael McGuire
83 300d
01 vw A4 TDI
66 Chevy Corsa
68 GMC V6 w/oD
86 300E

Thanks for the confirmation. The diaphragms will work properly for the single-diaphragm center vent pod, and the "small lift" portion of the dual pods. But for the "large lift" section of the dual pod, the movement is restricted to about half of normal travel!! I'm disgusted that George sells such a poorly designed, borderline defective, product. New pods are only about $30 each, and since they last 10-15 years, I think it's worth every penny. Plus if you break a plastic tab while rebuilding the old pods, you'll have to buy a new one anyway...!!

:p

1) I only get heat from the defrost function. I cant get heat from the two pushbutton functions to the right of the defrost function, I only get ice cold AC. No matter what range I spin the Climate Control knob, its cold stuff.
Is this a problem with the push button unit circuit card or one of the diaphragm pods?

2) Does anyone have experience with the Central Locking Vacuum Pump underneath the rear pass seat on the pass side of car? I cant get the A, B, or C 10V signal by locking/unlocking at the 3 main positions and it may be because this signal is routed through the oboard alarm which ihave disconnected. Can I use engine vacuum instaed?

1) That's definitely not vacuum related - you have an electrical problem of some sort. Could be the pushbutton unit, or a faulty temp sensor - you'll have to use the ACC manual to troubleshoot.

2) No clue on the door lock pump. You can't use engine vacuum though. Or at least that would be a bad idea. The older cars had a big vacuum reservoir in the trunk for the door locks, the 124 doesn't have that. It should not be tied to the alarm in any way. I disabled my alarm too (yanked the Becker brain box out from under the front passenger footwell). Used pumps should be cheap, but a new pump is stupidly expensive, if the pump is bad. I'm not sure what the problem is there either...! Now if you have an aftermarket alarm installed, you need to figure out what the installer screwed up!!!

Updated original post and fixed the link to the photos. Bump for new members. I'll post the list of part numbers too... stay tooned.

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Dave
Boise, ID
Check out my website photos, documents, and movies!

Added part number list to first post. Enjoy!