Modifications Of The Automatic Climate Control (83/75)
Publication date: 1991-06-01Reference number: 83/75
MODIFICATIONS OF THE AUTOMATIC CLIMATE CONTROL
TECHNICAL SERVICE BULLETIN
MODELS 124 AND 126 - MODIFICATIONS OF THE AUTOMATIC CLIMATE CONTROL - MODIFIED WATER FLOW CIRCUIT IN THE HEATER CORE ON MODEL 124 & MODIFICATION OF THE COMPRESSOR SHUTOFF ON AUTOMATIC CLIMATE CONTROL, MODELS 124 AND 126
Model(s): 1986-on Mercedes-Benz 300 E; 1987 Mercedes-Benz 300 D, 300 TD; 1987-1989 Mercedes-Benz 260 E; 1988-1991 Mercedes-Benz 300 SE, 300 SEL, 420 SEL, 560 SEC, 560 SEL; 1988-on Mercedes-Benz 300 CE, 300 TE; 1990-on Mercedes-Benz 300 D, 300 E 4MATIC, 300 TE 4MATIC; 1990-1991 Mercedes-Benz 350 SDL; 1991 Mercedes-Benz 350 SD; 1992-on Mercedes-Benz 400 E, 500 E
Group: 83 - Climate Control System, Automatic/Tempmatic A/C
Bulletin No.: 83/75
Date: June 1991
MODIFIED WATER FLOW CIRCUIT IN THE HEATER CORE ON MODEL 124
Since May 1990, a heater core with modified water flow circuit and a new version monovalve (Fig. Fig 2 ) are installed. They guarantee improved removal of air trapped in the heater Core (Fig. Fig 1 ).
| Model | As Of Chassis End Number |
|---|---|
| 124 (except for station wagon) | B249 838 |
| 124 station wagon | F146 108 |
PARTS INFORMATION
| Qty. | Part Name | Part Number |
|---|---|---|
| 1 | Heat exchanger (heater core) | 002 835 64 01 |
Additionally, if the new version heater core must be exchanged, the entire heater/air conditioning case must be removed.
To remove the heater core with the pipes, the support for the vacuum components (8, Fig. Fig 4 ) must be unbolted (3 bolts, arrow) and the linkage rod for the main air flap (arrow, Fig. Fig 5 ) must be unclipped.
MODIFICATION OF THE COMPRESSOR SHUTOFF ON AUTOMATIC CLIMATE CONTROL MODELS 124 AND 126
The compressor shutoff for gasoline-powered vehicles is modified as follows:
The compressor cycles (20 seconds on, 20 seconds off) if the coolant temperature measured at sensor B10/8 is above 122°C (previously 117°C). Compressor emergency shutoff occurs at coolant temperatures above 128°C (previously 122°C).
After this modification, the pushbutton control unit (N22) is the same for gasoline and diesel powered vehicles. This version can be installed in earlier production vehicles (as of September 1987).
PARTS INFORMATION
| Qty. | Part Name | Part Number |
|---|---|---|
| 1 | Monovalve | 001 830 20 84 |
IN CASE OF WARRANTY
OPERATION: Heater core, air in system (water noise)
DAMAGE CODE: 83201 86