A/C - ACC Production Changes
83mercedes03TO: OUR MERCEDES-BENZ PASSENGER CAR DEALERS
DATE: August, 1983 REF.. NO. MBNA 83/39
SUBJECT: A. MODIFIED TEMPERATURE SELECTOR WHEEL AND MODIFTED TEMPERATURE SENSOR MODEL 123.123
B. MODIFIED VACUUM SYSTEM MODELS 107,123 AND 126 WITH AUTOMATIC CLIMATE CONTROL
A. Modified Temperature Selector Wheel and Modified Temperature Sensor Model 123.123
Since August 1982, a modified temperature selector wheel and temperature sensor have been installed in Model 123.123.
FIGURE 1 - ARROW = RESISTOR (PREVIOUS VERSION):
Production Phase-in
Model As of Chassis End No.
123.123 359439
The previous version had the compensating resistor in the sensor's 2- pin plug (arrow, Figure 1). The modified version has the resistance integrated in the selector wheel.
The previous and modified version wheels and sensors are not interchangeable. In case of repairs on older vehicles, both the modified version wheel and sensor must be installed together.
Parts Information
Part Name Part Number
Temperature 126 820 05 10 (Previous version)
selector wheel 123 820 19 10 (Modified version)
Temperature 123 830 03 72 (Previous version)
sensor 123 830 06 72 (Modified version)
FIGURE 2 - VACUUM DIAGRAM, MODEL 107:
B. Modified Vacuum System Model 107, 123 and 126 with Automatic Climate Control
Model 107 (Figure 2)
Since August 1982, the restrictors for the main and center air flap vacuum elements are located upstream of the respective switch-over valves (14 and 16).
FIGURE 3 - VACUUM DIAGRAM, MODEL 123:
Model 123 (Figure 3)
Since May 1982 (Oct. 1982 for 123.193), the restrictor for the center flap vacuum element is located upstream of the switch-over valve (13). An additional restrictor is also installed upstream of the vacuum element (41) for the fresh air/recirculating air flap, to provide a smooth transition from fresh air to recirculating air.
FIGURE 4 VACUUM DIAGRAM, MODEL 126:
Model 126 (Figure 4)
Since May 1982, the restrictor for the center flap vacuum element is located upstream of the switch-over valve (13). In addition, the restrictor for the diverter flap vacuum element is located upstream of the switch-over valve (18) to permit the diverter flap to open smoothly, and; the restrictor for the fresh air/recirculating air flap vacuum element has been moved closer to the switch-over valve (17) to assure that the flap operates smoothly over its entire travel.
NOTE: The described locations are circled on the respective diagrams. The schematics for the previous versions are provided for comparison. The check valves (45) used in the previous versions have all been eliminated since they are not necessary with the relocated restrictors.