300SDL (126.125) L6-3.0L DSL Turbo (603.961) (1987)
Control Assembly: All Technical Service Bulletins
Campaign - ACC Pushbutton Control Unit
REF. NO.: MBNA 83/39
TO:
OUR MERCEDES-BENZ PASSENGER CAR DEALERS
DATE:
November 1991
SUBJECT:
MODEL 124 AUTOMATIC CLIMATE CONTROL PUSHBUTTON CONTROL UNIT INSPECTION/REPLACEMENT
In vehicles within the Effective Serial Number Range, the pushbutton control unit for the automatic climate control (ACC) must be checked prior to any
other repair in cases of climate control complaints, or during the vehicle's next scheduled maintenance or repair. If a customer's vehicle within the
Effective Serial Number Range has just recently been serviced i.e. the vehicle is not scheduled for another service in the near future, we suggest that you
contact the customer to schedule an appointment to have the pushbutton control unit checked.
Pushbutton control units manufactured by Bosch, part no. 124 830 33 85 (Canada version [~C], part no. 124 830 24 85), are incorrectly soldered causing
the unit to fail. Thus, the automatic climate control will only operate in the heating and defrosting mode.
The affected pushbutton control units are marked with one of the following production codes:
163, 164, 165, 166.
Control units with these production codes must be replaced as they will ultimately fail to function properly.
Bosch pushbutton control units as of production code 167 are correctly manufactured.
Pushbutton control units manufactured by Kammerer. part no. 124 830 31 85 (Canada version [~C], part no. 124 830 22 85), are correctly soldered, i.e.
they do not have this problem.
Effective Serial Number Range
Model
From Chassis End Number
To Chassis End Number
124
1B 501718
1B 574453
124
1F 180488
1F 191943
Determine whether or not the automatic climate control (ACC) pushbutton control unit must be replaced by inspecting which version is installed.
Procedure
1.
Remove center dashboard wooden panel by removing the two screws at the lower edge just above the radio.
2.
Inspect whether the pushbutton control unit is manufactured by Kammerer. Kammerer units are identified by the letters "MK" enclosed in a box on
face of the unit. If a Kammerer unit is installed, replacement is not necessary. The wooden panel may be reinstalled.
3.
If control unit is not marked on face of unit, then the unit installed is manufactured by Bosch.
4.
Remove (Bosch) automatic climate control (ACC) pushbutton control unit (see SMS, Repair Instructions, Automatic Climate Control, Model 124,
Job No. 635).
5.
Inspect production code information on back or side (frame) of control unit.
6.
Replace (Bosch) control unit if production code is 163, 164, 165, or 166. Do not replace control unit if production code is below or above this
range.
7.
Reinstall control unit and wooden panel.
Parts Information
Part Name
Manufacturer
Part Number
Part Number
USA Version (~F)
Canada Version (~C)
ACC pushbutton control unit
Bosch
124 830 33 85
124 830 24 85