dm33buckeyes

My EC light came on and i also notice that the engine temps would start to clinb in stop and go traffic, i did some looking and the radiator fan does not turn on. i checked the fuses and pulled number 4 which is abs/esp, ADS, automatic temperature control, blower motor AC, and engine residual heat system. Once the fuse was pulled the fan started right up, but once a new fuse was put back it stopped again. I was wondering what would cause this. Would low refridgerant have anything to do with this. 2000 E320

A/C diagnostics
1- 12
2-89
3-123
4-123
5-98
6-148
7-01
8-91
9-27
10-6.0
11-2.3
12-3.5
20-3.2
21-32
22-00
23-32
24-11.2
40-164
41-91
42-44
43-136
Error codes
234-sunlight sensor
419- ac cluch compressor
422-serial interface K1

mrboca

The fan is turned on either when the coolant temp goes above 105 degrees C or when the refrigerant pressure is above 15 bars or both. So if the coolant temp never reaches the 105 degree C level and the refrigerant pressure is less than the above, your fan will not turn on. The latter is obvious, as your compressor is not running, refrigerant is low (see the errors you listed). When you take fuse 4 out, you are removing power from the a/c controller (always on power= circuit 30). The controller cannot communicate with the rest of the system to report the refrigerant level, so the ECU / SAM turns on the fan by default.

Fix the a/c issue, and the fan should come on when the a/c is running and when the refrigerant pressure is above 15 bars (#7 in your list).

You should be able to check the a/c controller communication by pressing the BOTH AUTO buttons more than 15 seconds. The fan should come on at high speed.

Plutoe

Look at data point 7---you have little refrig--should be 15 bar--extract--hold a vacuum and refill--if cant hold a vacuum-- fix leak and start the process again---then putz with fan controller