Is there a way to lubricate this switch? Mine seems to work but is so stiff I fear I will break something moving it.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

It's a Bowden cable to the fresh air flap. I would try a drop of ATF.

If you remove the glove box and the upper control panel, it is possible to reach in there and detach the cable from the switch.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

whatever you do don't force it. if you rip those little plastic balls on wire apart in the switch you have to replace it. It aint cheap.

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1978 Mercedes 240D
1981 Mercedes 240D
1982 Mercedes 240D

Do you think its in the rotary dash knob, the cable or the electrical switch?

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Pure guess work. But from experience with my old 240D I'd suspect the Bowden cable itself. Agree with the opinion not to force it.

- Peter.

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2021 Chevrolet Spark
Formerly...
2000 GMC Sonoma
1981 240D 4spd stick. 347000 miles. Deceased Feb 14 2021
2002 Kia Rio. Worst crap on four wheels
1981 240D 4spd stick. 389000 miles.
1984 123 200
1979 116 280S
1972 Cadillac Sedan DeVille
1971 108 280S

Once you have the cable separated from the switch it should be easy to tell if the problem is in the Bowden cable or the switch deck. My money is on the Bowden cable.

There is a bayonet connector in line with the switch that allows the Bowden cable to be separated from the switch body.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

It is the cable, they get rusty inside from moisture....you can lube them but it needs to be removed in order to do this....chances are the cable is weak and it will snap soon after lubing it...I had the same issue...what I did was to leave the flap open and disconnect the cable from the knob, now that I have the box tore out...I am going to replace it.

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Thanks gentlemen! I have some ideas now to follow up.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I just bought the switch for $20.63, and hoping that is the end that has the little balls on a string...cause my string is broken and the little balls are missing. Oh...wait, that really sounds so wrong...

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1983 W123 300TD US spec Turbo engine, with Euro bumpers and manual climate control, and manual transmission.

that is a good price, here is the dealer price.


SWITCHA/C UNIT
Make: Mercedes Benz | New Part#: 1238200710List Price: $27.50
Your Price: $22.00


Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

I had to replace the fan-switch on a friend's Euro 300D because of this issue, as
the knob shaft had actually been twisted off. Lubing both ends of the cable with ATF made the replacement switch work perfectly.
But it 's a real pain getting to the switch end of the cable. You might try detaching and repeatedly lubing the cable-end behind the glovebox first. Then helping that end back & forth with a needle-nose pliers, while gently twisting the knob, to see if it will loosen up.

Happy Motoring, Mark

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DrDKW

I had the same problem in one of my 240D's. If it has the manual climate control with the center knob switch then I agree with the above comments. Long story short is it's the cable. The switch is dual function unit. It is both an electrical switch as well as a mechanical switch. The flap is where the problem is, the sheathing either swells up or the metal cable rusts in the jacket. A drop of ATF or machine oil with moving the cable should solve the problem.
If you twists the switch to much you will break the plastic mounting bracket which supports all 3 knobs controls. If this has happened, as in my case, I had to pull the center console apart. The bracket which supports the fan switch is secured to the evaporator housing.