Dear friends:

I'm still waiting for W126 service CDs and would like to know the name and function of the marked items in the attached image.

1) Cruise control or pneumatic governor?

2) What's the name and function of this black box in the throttle assembly?

3) No idea

4) AC low side?

BTW, I have changed the following oils/fluids on my 300SD and wondered if I'm still missing some other oil/fluid? I will tackle the bad blower motor and AC conversion/charging as soon as I have some free time. I hate Mercedes' vacuum-based door/trunk locks.
The Japanase electric/manual locks never failed me a single time, even on very old cars.

Engine oil
Brake fluid
Power steering fluid
Transmission fluid
Differential fluid
Antifreeze (Zerex-G05)
Windshield fluid
More water for battery's cells

Thanks a lot.

Eric

Attached Thumbnails

 

2 is the cruise control governor and 3 is the housing for the tachometer amp.

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W126 1983 300SD 286,000 miles and ticking
Baby blue exterior Grey MB tex
Recent work:
Replaced air cleaner mounting brackets and heat shields
Replaced alternator, fan and power steering belts
Replaced positive battery terminal
Replaced negative battery terminal and cord
New Duralast Battery

My car needs work.

I'm not sure what #2 is called but I don't think it has anything to do with the cruise control. AFAIK it houses the vacuum switchover valve for the transmission modulator and EGR and possibly has a mechanical throttle position input.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

1) cruise control actuator (electric motor that moves linkage in response to signal and feedbacks from CC amp)

2)"Black Box". Switchover valve(s) which control vacuum to trans modulator, EGR and recirc valve? (CA cars). (Little white levers that can wear out hide inside here).

3)tach. amp. (made famous by butt trick)/old diag. port

4) low pressure A/C hose (#12 size), also called suction side hose.

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The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)