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1996 E320
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Discussion Starter #1
Having trouble with my A/C in my 1996 E320. The A/C does not blow cold and I am unable to override the "Auto" function by increasing or decreasing the fan speed.

I ran the climate control diagnostic codes and had errors eb1 232, eb1 234. The report follows.
I presume I need to order an evaporator sensor and a refrigerant pressure sensor?
Can someone tell/show me with a picture where these sensors are located?
Are they easy to replace? Thanks.


# Your evaporator temperature sensor appears to be malfunctioning. Usually a bad evaporator temperature sensor is indicated by code B1230. Your car does not indicate this code. However, a bad evaporator sensor does not always trigger the code. The sensor reports a temperature of 91.4 degrees. The outside air is only 77 degrees. It's impossible for your evaporator temperature to be that much warmer than the ambient air. When the evaporator temp sensor reports a value like this (and nothing else is out of spec), your A/C should run for 10 minutes after starting the car and then automatically switch off. It does this is to protect the evaporator from freeze damage. The climate control system carefully regulates the evaporator temperature to make sure it does not drop below 33 degrees. If the temperature drops below 33, the moisture in the air may freeze and damage the evaporator. When the temperature sensor stops working correctly, the climate control system cannot tell whether the evaporator is too cold. It then shuts off to protect the system.'
# Code B1232 Explanation: This sensor measures the pressure of the refrigerant in the A/C system. It appears to be malfunctioning. If this sensor is defective, you may be able to turn your A/C back on by overriding it.
# Code B1234 Explanation: This sensor detects strong sunlight and increases the fan speed slightly to compensate for solar gain. The sensor is located in the middle of the dash near the windshield. This sensor is not critical. Its failure would not interfere with normal A/C function.
 

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2009 C63 AMG
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137 Posts
Can't help with your questions, but always thought it strange that the A/C light comes on during cool and cold weather when using the Auto function. Why is this and am I using additional fuel if I don't turn it off?
 

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Oo == oO 98 E320
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674 Posts
The a/c runs whenever Auto is selected to help remove moisture from the air, reducing the chances of the windows fogging. I turn off the compressor in cool weather unless I need to keep fogging down.
It may not use much fuel in cool weather as the compressor is variable but I vote for off.
Unless something has changed in recent years it used to be considered wise to run your compressor for a few minutes weekly year-round to keep the seals lubricated. Any comment from mechanics?
 

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2009 C63 AMG
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137 Posts
johnamoss said:
The a/c runs whenever Auto is selected to help remove moisture from the air, reducing the chances of the windows fogging. I turn off the compressor in cool weather unless I need to keep fogging down.
It may not use much fuel in cool weather as the compressor is variable but I vote for off.
Unless something has changed in recent years it used to be considered wise to run your compressor for a few minutes weekly year-round to keep the seals lubricated. Any comment from mechanics?

excellent information--thanks!
 
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