Stuck in EC mode. A/C never engages.

I have a 2001 Mercedes E320. It's hot summer now, but I can't turn AC on. I'm stuck in the EC (economic) mode. No matter how many times I push the EC button, it doesn't turn off. I checked fuses, recharged freon (actually R134a). None helped. I pulled the control console out last night, but could not see a way to fix the problem. All the wires are bundled into two clusters and pluged into two sockets. Any idea what I should do? Thanks a lot.

vic

Reply to
mbheadache
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The over/under pressure switch located on the receiver/drier has been known to go faulty. This switch will prevent the A/C engaging if there is too much or too little pressure in the system. If it is faulty then your system will not work.

Reply to
Stratman

Got the same car.... two times it went in to service because of EC... both time, they replaced the evaporator temperature sensor.

Your unit has a self diagnostic code display... if I remembered correctly... set driver temp all the way up and passenger all the way down... turn off and on the ignition and code will come up... I got this info on internet... do a search on this.

Reply to
Tiger

Thank you, Stratman and Tiger. I'll check the evaporator temp sensor and the pressure switch, hopefully this weekend. I just bought a set of repair manual CDs from Ebay. It says to turn driver temp all the way up and passenger all down, press the 'EC' and 'REST' buttons down together for 5-30 seconds, I'll get the self diagnostic code.

Reply to
mbheadache

I did the self diagnosis reading last night. Press 'Auto' on both side, then set temp to 72F on both side, then press 'REST' for 5 seconds, next is to read values on the LCD. Press 'Auto' for next value. The only suspicious value I saw was 7 on left side and 05 on right side. I looked up on the manual. It means refrigrant pressure is 0.5. That might be too low.

Reply to
mbheadache

Reply to
frank hodges

Then you got to charge it up.

Reply to
Tiger

Hi, this thread caught my eye due to my '97 C230's weak and intermitant AC.

Attempting the above, almost worked, but I needed to: [AUTO] temp at 72 (is this necessary?) hold [REST] for 5 seconds values appear on LCD as alternating 01 98f (I could change codes by pressing + and - of fan speed control)

others I got were

02 80f 03 79f 05 124 06 167 07 069 which I assume is refrigrant pressure of 06.9 ... I assume I need to re-charge the system, but I don't know what the other numbers mean, is there a link to this information?

BTW: upon reving up the engine the 07 number changed to 164 and stayed higher, and the AC blew colder.

reagrds, Bob

Reply to
Bob Sheff
02 -- outside temperature 03 -- heater core temperature (left) 05 -- evaporator temperature 06 -- ECT sensor (sorry, I don't know what ECT stands for) 07 -- refrigerant pressure in bar

I have a repair manual.

Reply to
mbheadache

"" wrote: > 02 -- outside temperature > 03 -- heater core temperature (left) > 05 -- evaporator temperature > 06 -- ECT sensor (sorry, I don't know what ECT stands > for) > 07 -- refrigerant pressure in bar > > > I have a repair manual.

Hey, thanks guys for this great topic here. I got a ?96 C220 with the same EC light on for over a year and didn?t know what the problem was with my AC not working. I followed the details here and found that at

07 it showed my refrigerant to be LO. So I filled in more R134a stuff and it showed pressure until I was able to physically press the EC button hold it in until it turned off and the compressor turned on and ac cold air came out.
Reply to
MBSam

Where can you get the shop manual from ? I want one for a "2000 E320".

Does anyone know what the refrigerant pressure should be ? Mine was 04 the first time I checked and 06 the second time I checked after running the car for a while. My EC light is also stuck. My readings are as follows.

1=80 2=78 3=91 4=85 5=80 6=152 7=04 8=78 9=27 10=.8 11=2.8 12=4.2 20=3.2 21=44 22=00 23=32 24=13.3 and 13.5 (switches back and forth) 40=164 41=85 42=40 43=136

MBSam wrote:

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Reply to
ron_gouldner

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