Dear all,
I recently brought a w211 E280 cdi facelift. the car is well maintained and has no errors on the scan.

About a month ago the ac stopped cooling and after inspection it was found that the compressor was spoilt ( sliver shavings in the compressor oil and no compression) . Further found out the filter was clogged, and so changed the condenser+ filter+pressure switch + compressor and expansion valve, flushed the system and pressurised. Yay i taught now what can go wrong.

So here is the issue:
1) The compressor does not start until the temperature of the engine reaches 80 deg +.
2) When it does it cools until it freezes the evaporator coil ( temp showing 0deg and 1 deg on the hidden menu 5), it does not show a On/OFF switching that one would expect the system to follow. It cools till freezes and then switches off.

Have scanned it and there are no faults on the system, the one that showed up on on of the scans after rebuild was 9450 B31 (c-aac Stored multifunction sensor)

further probing into the AC actual values showed a B12/2 sensor at -99deg which is wrong i guess, could be a bad connection etc but have no idea where this sensor is.

SO has anyone a suggestion on why the AC is not cutting the compressor?
Also does anyone have the diagram of the wiring or sensor placement in the car? Service manual?
This would help me alot thanks.

 

Somehow this script will not display the picture, so I found the actual WIS page.
That applies to 320 engine as 280 is not recognized on American site, but hopefully yours will be the same.
http://workshop-manuals.com/mercedes...rature_sensor/