Just got a 300SD cuz the new oil cooler line I installed in my 300D failed. ("Why is this thing running so rough all of a sudden?... oh... dammit!) Both had similar cooling issues (hot air at all times, new monovalves in both, AC only works in the SD...) so I wanted to pull the ACC control unit out of the 300D, refloat all the solder connections and see if that worked in the 300SD. Are they the same units? Are they similar enough so that I can use it, at least temporarily? In the 300SD, the fan seems to work normally - ramps up every few seconds to full, but in eco mode blows hot, when AC is on it blends hot with the AC and full hot in the upper vents. Pulled the connector to the monovalve to see what effect that would have, and it actually had no effect - still blows hot air. Any suggestions on where else to look would be appreciated.

In the same vein, can I swap cruise control computers?

I know the seats are different, but are the seat spring boxes the same?

r

mjk
84 300SD (CA car) 90,300 miles

Can't say for sure on the ACC unit, but if you look up the part numbers for the two vehicles, they are different.

I can't give an answer on the other items, but try looking them up on the marecedesshop parts link. ************************ has great diagrams also.

You might try checking the cabin temp sensor(located at top center of dash)- it should have a certain resistance reading. Also, make sure the tube from that sensor to the blower is in good shape, otherwise the ACC wont be getting accurate temp readings.

__________________
'83 300D Turrrbo 295K miles

Not exactly. The SD has an additional ventilation flap/actuator.

From what I have read the seat spring box is the same on the 123 & 126.
The 126 has the electric seat motors, it unbolts from the seat bottom.

also the spring box from the pass. side will fit on the drivers side.

Charlie

__________________
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

Disconnecting the mono valve causes it to default to full heat. When 12V is applied it shuts off the flow of water. Before you replace the ACC check your Aux pump. If it's shorted or drawing too many amps it will fry your new ACC. This could be the reason it's blowing hot...no 12V to the mono valve. You can disassemble your ACC & look at the PC board. If the Aux pump is bad you should be able to see a burned trace on the circuit board & repair it. It's also a good idea to install a fuse (about 1 amp) inline with the Aux pump to protect the ACC from an overload. If the Aux pump is bad it can be unplugged with no harm to the system. The only drawback is low water flow at idle causing a drop in heater output.

__________________
82 300SD 202K
82 300SD 233K
83 300TD 340K
82 300TD 98k euro (parts on the hoof)
85 300TD 282K
83 300TD 197K

The two ACC units of that model year are physically the same. What is different between the two is the circuitry. As stated above, the w126 ACC has an additional actuator to control. The W126 ACC unit will work on a w123 just fine. But a w123 ACC unit will not work properly on a w126, although you might be able to use it for temporary testing purposes.

Also as stated earlier, check the monovalve and Aux pump.

__________________
1983 123.133 California
- GreaseCar Veg System