E320 4matic wagon - no air - Mercedes-Benz Forum
 
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post #1 of 8 Old 08-06-2019, 02:20 PM Thread Starter
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Question E320 4matic wagon - no air

2002 E320 with no air is not cool. The EC button stays on and I cannot turn it off, which turns on the air conditioner/climate control. The system is not low on freon. There is a sensor that might be the culprit, but I don't know where it is located or what it looks like. If this sensor is malfunctioning, it would prevent the EC light from being turned off. Help !
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post #2 of 8 Old 08-07-2019, 01:07 PM
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The system monitors several things. You said it is not low on freon.

What are the pressure readings on the low side and high side ports. Too much pressure and it will shut down to protect itself.

Have you had the car scanned with a scan tool that can read the AC codes?
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post #3 of 8 Old 08-07-2019, 04:10 PM Thread Starter
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My tool won't scan AC codes. I don't have pressure readings. Can I use a tire gauge or is there a special gauge to test high and low sides? I was going to replace the AC sensor to see if that would allow the EC switch to turn off. But I could not locate the EC sensor, despite having a diagram.
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post #4 of 8 Old 08-08-2019, 10:45 AM
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Many of the big box parts stores loan the AC gauge set that you would connect to the low side and high side port.

The values can change based on ambient temp. The correct values are easily found on interweb as they are the same for almost all cars.

AC Pressure Chart | R-134a Temperature Pressure Chart
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post #5 of 8 Old 08-09-2019, 09:03 PM Thread Starter
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Thanks for the link to the AC tutorial. Tutorial said that as my compressor is not cycling (because the EC light won't turn off), I cannot get accurate pressure readings. If I can get the EC light to turn off, then the compressor should cycle. My research shows a faulty AC sensor could be the culprit, and not allowing the EC switch to work. How do I get the compressor to cycle? Is there a way to by-pass the EC switch? Or??
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post #6 of 8 Old 08-10-2019, 04:24 AM
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I do not know of a way to bypass the switch.

The W210 can actually show some AC diagnostics on the AC display panel. I will look them up and post them this evening.
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post #7 of 8 Old 08-11-2019, 03:20 PM Thread Starter
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Thanks, Noodles. Can you guide me to where the AC sensor is located?
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post #8 of 8 Old 08-12-2019, 08:40 AM
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Are you referring to the pressure sensor or the sensor for the evaporator?
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