DaveyN

97 SL5OO with single zone a/c. Put in new condensor and recharged, but EC light stays on. Ref. temp switch OK, and if you hold EC button with engine running it will go out and the a/c will start. But it comes back on again when next starting engine.

Canit be done on the panel, or does it need a special diag. tool?

mbtech208

It shouldn't be coming on at all. Usually the EC light stays on due to a low refrigerant charge. Are you sure the A/C system was fully charged? It might be blowing cold air, but the refrigerant level could still be low. Also make sure there aren't any leaks still present. Why did you replace the condensor, was it leaking? Any time the A/C system is opened to the atmosphere, you should replace the receiver-drier too, because it rapidly absorbs moisture from the air, reducing its effectiveness.

DaveyN

Thanks MBtech208. I had a stone go through the condensor and the EC light came on same time, so replaced with a new drier. Charged with 950gramms and 60ml pag.

If I hold the EC switch for 10 secs and it goes out, compressor starts and runs, and low side pipes get cold, until I switch engine off again.

From a tech disc I got the following: To clear DTC fault codes, switch ignition on, within 10 secs press recirc/REST/temp arrow up at the same time for 2-4 secs, then diplay should show --- . But this doesn't do anything. I spoke with MB, but they just said put it on the Star, but they always say that!