Hey, is this a good price for a NEW climate control servo ($950) for a 123 diesel?
If so, is it a royal pain to install? How often do these things fail anyway (my car is an 84 300 CD)?

I'm told that this may be the reason my temperature fluctuates so much and possibly why the floor vents won't open. And yes, I've replaced and/or checked all the less expensive stuff first, like the vaccum servos and mono valve. All are ok.

The only other thing I have yet to mess with is the pushbutton unit, which I'm told has little effect on vents opening or not. Barring a vaccum leak, the climate control servo is likely to blame, they say.

I really don't want to have to replace the servo if I have to, but what does anyone think of the price?

Thanks

Gil

$900 is way too high, $400 is what a new A/C Servo should go for. I learned a trick that made mine work better, I would problems with it being too hot, or too cold or it would just stop working when I was on a long trip. Try setting the temp to 65 and have it on high, do this for maybe 5 minutes, then put it on defrost for 5 minutes. Switch back to high for another 5 minutes, and just keep switching back and forth for a while. This sometimes will help make them work better.

So, in the event I still need a new one, where can I get one for $400?

Thanks

Gil

Even $400.00 is to much for this part. You can can a rebuilt unit for $ 181.80 plus a $ 200.00 core charge which you will get back when you return the core. I have delt with this company for three years. They are one of the best ones I have found with reasonable prices on parts that come in a MB box or plastic bag.

Give then a try, I sure you will have good luck with them.

http://www.sasponline.com/

MBJOE

I bought a metal bodied servo recently from Randy at European Auto Parts (?). Do a search on servo and his web address will come up. Very good to work with.
Seems much better than the original. But you won't have one on an 84.
For anyone looking for a servo, they were also used on Chrysler Imperials (?) so you might find a used one there also.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

My 6.9 has one of George Murphy's aluminum bodied servos in it and I have not experienced any problems whatsoever with it since installation about four years ago. I went through two servos on my W116 300SD, should have put the aluminum one in to begin with. Got about three years out of the one I originally put in.

__________________
Regards,
Aaron

Okay, now it makes me feel better that I never noticed this big black box under the hood. The guy on the phone was acting as if the 123 series all had them... maybe he's new.

So, then, the problem with the non-opening floor vents can't be a servo unit, so that brings me back to the climate control (pushbutton) unit. Any thoughts on the likelihood of that part causing the floor vents to not respond?

Gil

Have you checked the switchover valve? I assume you have checked to make sure there is no vacuum getting to the servo when the pushbutton unit is the appropriate position. The pushbutton unit activates a small valve behind the unit which sends the vacuum to the servos. They are electrically operated and fairly inexpensive.
You have to remove the pushbutton unit and look just up and behind the pushbuttons.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

I replaced all of them, or so I thought... I'll check them all again, but It's odd that niether side of the floor opens at all, and the pushbutton unit seems only able to direct air to the windshield and side vents no matter what button is pushed.

Gil

These pushbutton units seem to be a problem area.

Mine sounds like it's shorting out, even when it's turned off. My air cycles from the floor to the windshield all by itself, and it's only about 2 years old.

These guys:

http://www.gdl-online.com/begin.html

They will do a check of the unit for $25 and a rebuilt one is about $185 with a 1 year warranty, which is what MB gives you on a new one.

Kerry- Where do I look for this valve? Does it have wires going to it? I don't think this is my problem, but I'll check anyway. My pushbutton unit is just hanging there because I've been meaning to send it in.

Craig

__________________
1994 E420, Pearl Black/Black. 2.82 rear diff., AMG front spoiler, painted lower half. SOLD

1972 & 1974 BMW 2002tii's.

There are five of them in a row mounted behind the pushbutton unit. There are two vacuum lines and one wire (?) going to each one. They can be tested by putting 12 volts to them and seeing if they open and close so that vacuum can flow thru them.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Thanks Kerry. I've never checked these before.

Craig

__________________
1994 E420, Pearl Black/Black. 2.82 rear diff., AMG front spoiler, painted lower half. SOLD

1972 & 1974 BMW 2002tii's.

I fixed my PBU last week by reflowing all the connections inside. It is a reman unit and I assume that means they have gone over all the copper traces with solder as that was what looked like was done. I just reheated all the pins where they came through the boards, and then went over all the traces for good measure. This fixed many issues I had with heat and defrost. Lower vents now open for the heat, fan runs at whatever setting I put it on, and I have heat when I want it.

see George Murphy's article attached.

Attached Files

mb_cc.txt (13.4 KB, 291 views)

I thought about doing that but I think once it's been re-done, it can't be done again. Do all the functions work after you re-soldered it?

Craig

__________________
1994 E420, Pearl Black/Black. 2.82 rear diff., AMG front spoiler, painted lower half. SOLD

1972 & 1974 BMW 2002tii's.