A/C - Control Module, Production Modification

REF. NO. 83/84

TO: ALL MERCEDES-BENZ PASSENGER CAR DEALERS

DATE: May 1996

SUBJECT:
MODELS 140 AND 202 AS OF SEPTEMBER 1995, MODEL 210
A/C PUSH-BUTTON CONTROL MODULE (N22)
A. MODIFICATIONS TO PUSH-BUTTON CONTROL MODULES
B. SERIAL INTERFACE, INSTRUMENT CLUSTER (A1)
C. VERSION CODING PROCEDURE WHEN REPLACING PUSH-BUTTON
CONTROL MODULES
D. VERSION CODING USING THE HAND-HELD TESTER (HHT)

A. MODIFICATIONS TO A/C PUSH-BUTTON CONTROL MODULES





PARTS INFORMATION

Refer to table shown for application of part numbers.

Models 140 and 202 for model year 1996, produced as of September 1995 and model 210 since start of production; A/C push-button control module (N22) is equipped with a serial interface (K1). As of November 1995, all replacement push-button control modules (N22) are equipped with a serial interface (K1), that will be required in the forth coming model applications (refer to subject B).

Note:
The new push-button control modules can be installed in model year 1996 models 140 and 202 built prior to September 1995.

B. SERIAL INTERFACE, INSTRUMENT CLUSTER (A1)

Serial interface (K1): data link from instrument cluster (A1) to push-button control module (N22)

^ Model 202 in instrument cluster (A1), as of September 1995.

^ Model 210 in instrument cluster (A1), with start of production.

^ Model 140 not available in instrument cluster at this time.





Note:
Arrows shown in Figure 1 indicate direction of information or control signals.

The following signals are transferred via the serial interface K1:
Outside air temperature, engine coolant temperature, vehicle speed, engine speed (RPM), instrument cluster illumination (circuit 58d), °F/°C, fuel safety shut-off (diesel engines), acceleration recognition (gasoline engines).

C. VERSION CODING PROCEDURE WHEN REPLACING PUSH-BUTTON CONTROL MODULES

Models 202 and 210:
The engine version is automatically transferred from the instrument cluster (A1) by the serial interface (K1) to the push-button control module (N22). Other version coding is done using the HHT as described in subject D.

Model 140:
Version coding is done using the HHT as described under subject D.

Note:
The push-button control modules (for model 140) are shipped from the parts distribution centers (PDC's) with the following settings:

^ Model 140 with °C active

^ Engine 104 active

^ Smog sensor: with activated charcoal filter active





^ "Smog" readout (a, Figure 2) in push-button display inactive (switched off)

^ Refrigerant fill level check: active

^ Auxiliary fan (M4): active

^ Blower motor speed level bar display (not displayed in [auto] mode).

D. VERSION CODING USING THE HAND-HELD TESTER (HHT)








Note:
The tables shown describe version coding using the HHT, the actual HHT screen display may vary.

When performing version coding follow HHT screen prompts as indicated.