I have a 97 E320, the AC wasn't working properly for a few months (the blower relay thingy). I saw the tutorial on how to fix the problem using the relay from the S Class... I fixed that and now thats all good. Now, the AC blows cool (not cold) from all front vents when "first" turned on, then about a minute later it no longer blows for the "center" vents (just above the AC control) but still blows strong from the corners. It seems that when it stops blowing from the center ones, it starts blowing on the winshield (winshield gets fogged if it's night time) it does this same exact thing every single time I turn the AC on. It has been doing this for about a week now (since after the relay fix). One other thing I have noticed, If I'm driving with out the AC on and roll the windows up briefly, "warm" air starts to blow from the "side" vents (actual warm air, like the heater is on), what could be causing this? I can't even dress nice and drive my car, I start sweating Any suggestions?

Leon

 

Your problem could be complex. My initial suspicion is that either the in-cabin temperature sensor is way off, or your flap controller isn't doing its job. You'll probably end up taking the car to a specialist.

Run all the diagnostics described on this page:
http://www.continentalimports.com/ser_ic40142.html

Post here all your results from the diagnostics... sensor values, error codes, and flap test results. Also please post your estimate of the outside and in-cabin temperatures when you ran the test.

I (and others I'm sure) be happy to take a look at the results to see if there's something obvious.

 

Hi Lexrex,

Have you finished tweaking your A/C program? Thanks again for creating that, it sure helped me last year. Good Luck to Down South!

 

Will do! It's raining out now, so I'll try and do it tomorrow when I get off! Thanks

 

Stats are in:

Sensor 1: 27

Sensor 2: E

Sensor 3: 14

Sensor 4: 13

Sensor 5: 14

Sensor 6: 77

Sensor 7: 14

Sensor 8: 53

Erroe code: B1227 (only code that came up)

After running the values and error code through "EclassBenz.com" I got this
as an explanation.

"# Your climate control data has been received.
# Your sensor values were automatically converted from Celsius to Fahrenheit. All temperatures on this page are given in Fahrenheit and pressure in bar unless otherwise noted.
# 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 57.2 degrees. The outside air is only 32 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 B1227 Explanation: This sensor measures the temperature outside your car. It is reporting an implausible temperature.
# We hope that this diagnosis tool helped you solve your air conditioning problem and maybe even saved you a bunch of money. If you found it helpful, and would like to say "thank you," please consider making a contribution."

I Think that "middle" paragraph explains why shortly after turning on the AC, the middle vents stop blowing.

Tell me what you guys think...easy fix?????

 

My A/C program on EClassBenz.com is a little bit off the mark on this one, but close. My human diagnosis: The car doesn't have an accurate reading on the outside temperature (as indicated by code B1227 and sensor value #2). The car thinks it's freezing cold outside, hence the "defroster" vent behavior.

I suspect replacing the outside climate control temperature sensor will fix your air conditioner. Of course I can't be entirely sure; it's possible that the effect of the bad sensor is masking some other problem.

 

Will replace both those sensors within the next week or so and report back my findings...Thanks! Does the AC need to be reset or anything once any new sensors are installed or just repalce them and turn the AC on???? Do you know the part number for the outside temp sensor?

 

Although the evap temp sensor does seem to fail often enough to make replacing it good preventive maintenance , I personally would replace the outside temp sensor first before replacing other parts. No need to replace two sensors if only one is causing the problem!

Sorry, don't know the part numbers.

 

To clear the code, follow the instructions for viewing the codes. After viewing all codes (in your case, the one code), press and hold both AUTO buttons for at least two seconds to clear.

 

Ok, I will head out to the dealer Wednesday to source the outside temp sensor!

Leon

 

I looked up the outside (ambient) temp sensor and found this pic! Being that this is so long of a wire, where the heck does it plug up to?

 

Keep in mind that there are two ambient temp sensors: one that reports the temperature in the instrument cluster and the other that hooks into the A/C.

AllData doesn't list the location for the HVAC ambient temp sensor. I'll check some other sources.

 

My cluster "NO" longer reports the temperature anymore. I hopped into my sisters CLK to move it from behind my car and I saw the temp on her cluster before I even started the car. I know something is definately going on with my sensor. Going to the dealer tomorrow to order the one that goes in the front bumper. I went to change my fog light bulb (drivers side) today and as I folded down that lil flap right behind the fog light (underneath) a plug hung down...looks like something had been unplugged from it, could that be where the outside temperature sensor plugs up to???

Leon

 

I went and got the outside temp sensor this morning, I will post pics of it when I get home and also the part number. It was $20

 

I went home on lunch break and installed the sensor and now the dash is reading - 37...how can I correct this to make an accurate reading? I'll post pics when i get home.

 

Is it 98f where you are? if so you are in centigrade mode.If not system is out of wack.Also look at the post above,the little probe that plugs into the bumper is only a nice feature to show the outside temp on your dash,it's not the sensor that helps supply the a/c with the data it needs to operate.
good luck
ohlord

 

So you're saying that it's the Evap Temp sensor like the diagnosis states in the above post?

 

So you're saying that it's the Evap Temp sensor like the diagnosis states in the above post? On Eclassbenz.com it states that the "first" 8 sensors are related to the AC, the outside temp sensor in number sensor # "2"!

 

So you're saying that it's the Evap Temp sensor like the diagnosis states in the above post? On Eclassbenz.com it states that the "first" 8 sensors are related to the AC, the outside temp sensor in number sensor # "2"!

 

I got in the car to leave work and the temp is reading correctly now. I guess I have to go back to the dealer to order the evap temp sensor. Here are pics of the outside temp sensor.

Edit: I just went outside to run the codes again...the only one that came up was b1227

 

Post the values and let's take a look.Lexrex did the program and i'd be inclined to his suggestion.Run the car with the a/c off until operating temp is reached ,then turn on the a/c for 5minutes at 62f and then do the 72/72 diagnostics test.That way we can see the values of the system warm.
There are two sensors for outside temp.You replaced the one that indicates the temp on the dash.The other on goes to the a/c system and that looks like the failed part.Do what the boss man(lexrex) says and replace that first,run tests again and clear code.If it reads in range and the code is gone you should be going cold again.If not then replace the evap sensor and repeat.Mine showed the same code plus the sun sensor code and a few others.replacing the evap sensor cleared all the codes except one and that cleared with the reset function.
Hope you have the same luck.
ohlord
autohausaz.com has them for much less than the dealer and if you are over 50 bucks they ship free so i had them throw in a air filter and oil filter and it still was less then the dealer.

 

Stats are in "again"

just went outside and ran another diagnostic test

sensor 1: 23

sensor 2: 40

sensor 3: 13

sensor 4: 12

sensor 5: 15

sensor 6: 84

sensor 7: 15

sensor 8: 57

error code: b1227

After running the test on "EclassBenz.com" again, this is what it said this time....

"# Your climate control data has been received.
# Your A/C system is working properly. The evaporator temperature is 15 degrees.
# If your problem is air flow, rather than air temperature, it's likely that your blower regulator went bad.
# Code B1227 Explanation: This sensor measures the temperature outside your car. It is reporting an implausible temperature.
# We hope that this diagnosis tool helped you solve your air conditioning problem and maybe even saved you a bunch of money. If you found it helpful, and would like to say "thank you," please consider making a contribution."

Now what

what's the other part number/location of the other temp sensor for the AC that you mentioned so I can replace it?

 

Looks like that was the correct sensor. The evap, right, and left sensors are all in agreement, so there is nothing wrong with the evap sensor.

The sensor values indicate that at the time you ran the test, it was 104 degrees outside and the air blowing out of the vents was 55 degrees. Does that seem right to you? 55 degree A/C with the car running parked on a hot day is not really cause for concern.

I noticed that your refrigerant pressure is 15. I don't know what units it's using. Most W210s report pressure in units of bar and temperature in fahrenheit rather than psi and centigrade... If that's 15 bar, that's good. If that's 15 psi, that's really low. If you turn the fan speed to about 3 or 4, do you hear a strong hissing noise from the center vents, which would indicate low refrigerant?

Can you get a passenger to record the values while you're driving and the vents start misbehaving?

The air routing problem may be in the control unit or the flap valve actuator. Try this: Put the system in AUTO mode on both sides. Drop the temperature to LO on both sides. What happens?

 

Let me sum it up like this, I bought the car from my mom 2 months ago. Shortly before I bought it, she mentioned that the AC wasn't working. Before that when it was working properly, it was ICE COLD and it's nowhere near ice cold now. I'm trying to get it back working like how it use to, it just blows COOL air now, not COLD air. I do recall hearing a hissing sound last week sometime, but I don't really use it (the AC) that much because it's not working properly. How exactly would the passenger record the data while I'm driving? Tell me so I can give it a shop with a friend. It was not 104 degrees outside when I last did the test, it was night time, so I know it wasn't that HOT.

 

Just drive the car and put it in diag mode,and record the numbers.It really is pretty neat to watch all the values change as the car changes operating temps etc..
http://www.eclassbenz.com/node/27

have someone jot it down
(1-8)every 5 minutes

Then run the individual flap test at http://www.continentalimports.com/ser_ic40142.html

see if all your flaps are working
good luck
ohlord