'99 e300d - air conditioning not working
 

I haven't been able to get the air working on my car. It's "new to me", juts bought in January. Yesterday was the first time I tried using the air, no-go.

I should note, I don't have the owner's manual so maybe I'm missing something. I set the temp to "low", turned the fan up and put it on recirculate. Am I missing something simple?

Is the "EC" lamp illuminated on the pushbutton module, and does it fail to extinguish when you press the button?

With a car this complicated, you would be well advised to obtain a copy of the owners manual. If EC is on, no cooling will happen. Steve

For AC mode, you want to red light on the EC button to be off. Usually, the fan would be in the Auto setting and temp ~72. Compressor would then cycle on and off as needed to maintain temp setting.

Answer MattL's questions if that doesnt help.

I accidently left the manual in Montreal at my dad's place. I vaguely remember the PO mentioning EC... is that economy? I can't say I really noticed the light so I'll check that after work.

So, if I turn that OFF, and with the temp on LOW, it should be pumping cold air, right?

That's correct.

It may also be low on freon. Mine has a very slow leak and after a while, it won't put out any cold air. If the compressor is cycling, you will notice a "click" and see the engine load up a little while idling.

No dice. Nada.

I noticed that the compressor doesn't seem to be kicking in. No "click", no drop in idle. If there was a leak, wouldn't it be cycling?

I checked fuses 4 & 7, both are fine. What's the next logical step? Is there a relay I should test?

I have the little sister to your car, its E320, the most expensive surprise with 210 cars when it comes to A/C repair is the darn evaporator, it normally costs somewhere close to $3K to replace the darn thing. Anyone with high mileage 210 is going to face the music sooner or later.

Vahe

Does the red light on the EC button go off, or is it always on?

Does the fan speed increase when the "+" button is toggled in EC mode?

If I hit the EC button, the light comes on. If I hit it again, it goes off.

Yep!

Visually determine whether the compressor is turning with the EC lamp off. If so, you could have a heater fault or very low refrigerant (but still enough to start the compressor). If not, and the pushbutton unit doesn't notice, I have no clue what could be wrong. Perhaps it's a bad pushbutton unit.

Note that it is not normal for your compressor to cycle on this model. The only reason that the compressor should ever shut off is the evaporator getting below 37F. The compressor does not cycle off if cooling is not demanded; rather the heater starts up.

OK, by "visually determine whether the compressor is turning" I take it you mean the center of the pulley. No, it's not moving... only the outside "ring" that the belt touches is turning.

Is there another relay, fuse or elctrical connection I should be checking?

Thanks!

Engine off, key on. Put the left side temp of the CCU on HI and the right side on low (or is it the other way around?) then press and hold EC and Rest for 5 secs. You have 20 secs to do the above. If you take too long just turn ign off and back on and go straight to holding the buttons for 5 secs. Now press right AUTO button to view and toggle through error codes then post. FF means no stored codes. eb1 234 is a code.

Second, turn engine on. Set AC to 72f and AUTO and let warm up. Press and hold REST for 5 secs. Post actual values 1 - 8. Toggle using auto button. Press rest to exit.

There is a fuse in the electromagnetic clutch, but the pushbutton unit should notice if it has blown. Perhaps yours does not for some reason.

If you disconnect the clutch connector and check the clutch coil for continuity to ground, you can determine if this fuse is blown.

Also perform the procedure above to extract the codes and sensor values.

eb1 231
eb1 234
E ff

OK. My display reads in *C, not sure how to change that to F. I set the climate control to 22*C.

1 - 23
2 - 14
3 - 41
4 - 42
5 - 14
6 - 74
7 - 01
8 - 22