W210 Climate Control problem
 

1997 E420...
The ac blows very cold, and I replaced the voltage regulator but no change.

The Climate Control unit shut on and off, sometimes. It will reset itself to another temperature and fan value. When it does, the recirc light blinks once. As it happens, the blower turns off and then comes back on a few seconds later. The problem seems to occur for no reason, and the blower (flickering) always happens when coming to a sudden stop...

What are your thoughts? Oh, I also replaced the fuses...

As I run the AC diagnostic test, I get the following values
1 23
2 54
3 23
4 23
5 50
6 87
7 14
8 50
9 04
10 1.6
11 3.6
12 4.3
20 2.3
21 06
22 00
23 00
24 13.1
40 71
41 34
42 00
43 152

please help....

#5 value seems way too high, maybe that sensor needs replaced.

Great, thanks, what do you base this on, what are the expected values?

I believe #5 is the evaporator temperature sensor in degrees celcius. 50 C = 122 F Since you AC is blowing cold, I know the evaporator is not at 50 C. Did you run this test after the AC ran for a least a few minutes? My 97 E320 #5 value levels out around 4 when I set the temp at 72 and the car has cooled down. Your core temps 3 and 4 also seem a little hi too. What was your temperature settings? One more thing, #7 should also drop when the car cool down. If the system gets a high reading from the evaporator, maybe the compressor is running hard trying to cool down.

I may be way off base, just taking from how my car behaves and all the reading I have done online.

Thanks, I will try to post all values from 1) when the car is cold, 2) when the car has been running with the ac on at 72 for at least 10 minutes.

Checked #5 value this morning, about 45 ...
So the evaporator temperature sensor is bad.
I suppose the sensor is causing a condition that cuts off the climate control unit, making it restart and having interrupted the blower in the meantime.
Wish I had realized this before spending the money replacing the blower regulator -- I suppose I was due for a new one afer 100k anyway.

I hope someone else would chime in as I am in no way an expert. I mean you could have other issues, did you check for any error codes using the climate control unit? The good side is that the sensor only costs about $40.

I have a similar issue with the AC as I mentioned a week or so ago. I also believed, that after I replaced the compressor + dryer + recharge the system, is not working because I was getting Eb1230 error code when I run the Diagnostic Trouble Code . I did changed Evaporator Temp sensor but the AC still did not work. I checked the fuses - they were OK. I did released some of the refriugerant to reduce the system pressure - resulting in AC working again. However the aux fan (the driver side fan - there are two fans in front of the radiator) wasn't kicking in. I replaced the fan assembly. The AC is working but the aux fan is still not kicking in and the DTC error code is the same Eb1230 indicating a faulty Evaporator Sensor.
Any suggestions are welcome. PAT

After replacing the sensor, try reporogramming the unit. See the second page here - http://www.peachparts.com/shopforum/tech-help/86110-210-chassis-climate-control-problem.html

Len

Len,
thank you for suggestion. However, I did replace the ET sensor and reprogrammed the unit with no change in the outcome. Actually I tried 2 new ET sensors with same results: error code Eb1230 is still showing.
I also replaced the aux fan because wasn't kicking-in. The new one is still not kicking-in and the same Eb1230 error is shown. I just shorten the vertical 2 pigtail connector from the dryer by placing a copper wire connecting the two terminals, to see if the aux fan will switch on. I will take the car shortly for a spin to see if anything changed.
PAT

After I did the test drive I have a second error:
1. Eb1230
2. Eb1233 (refrigerant temperature sensor) new error.
The new error showed up after I shorted the vertical mounted pigtail connector of the receiver-dryer.
PAT