My EC light will not extinguish.
I ran the codes and I'm low on refrigerant.
I would like to add some dye and refrigerant so I can find the leak, but the EC light will not go out, and the compressor will not turn on, so I am not able to add the refrigerant.
Is there a way to erase this safe shut down feature so I can add refrigerant?

Thanks,

Mike
99 E300D

I'm afraid you are in the same situation I was. 99% certain your evaporator is leaking.

http://www.peachparts.com/shopforum/diesel-discussion/377507-w210-compressor-seized.html

Stop leak won't fix this. I tried a couple years ago and no luck.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

You can add refrigerant with the compressor off. If the pressure is below the AC clutch shut off threshold, you have to. Also you can check the pressure in the AC system through the CCU.

Sensor 7
http://www.mbcluster.com/Old_Website/Media_Diagnostics/W210%20-%20Airco%20Sensor%20Reading.jpg

Try spinning the compressor (center part of the pulley) by hand. If you can turn it through 360deg by hand, your compressor is not seized. It could simply be low on refrigerant or have a bad clutch coil.

__________________
CENSORED due to not family friendly words

I figured it out. To get the red EC light to go out you need to clear the fault codes.
Left HI, right LO, hold EC & REST for 5 seconds, after the fault codes appear then you need to hold both AUTO switches at the same time. This clears the red EC light, the compressor will now work and allow you to add freon and dye. I've got my fingers crossed, hopefully it's not the evaporator.

I was trying to let the OP know that there is a high probability that their evaporator is leaking. Mine was. It is a well known problem with the W210. I kept topping it off until finally it could not take it any more and the compressor locked up. Most likely because I kept adding refrigerant and not adding more oil also.

If the OP changes out the evaporator now, before their compressor seizes, chances are the rest of the system will be fine and they won't have to do a total system replacement. If however they wait until the compressor seizes then they will be replacing everything due to the parallel flow condenser and evaporator.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech