97 E320 Air Climate Control Unit

[Colin]

Bought the car two months ago, after owning the vehicle for four or five days the battery went flat, I took the car to Northwest Eurosport and the mechanic recommended installing a new battery, three days later the new battery went down again.
I identified a intermitent clicking coming from the Mono heating valve and ran a volt meter on that lead and sure enough, the valve is recieving power from the battery with the keys removed from the ignition 24 hrs a day.
I assume that the in dash air climate control unit, part # 230 830 2285 is the culprit.
Now to my 3 part question,

Can this unit be tested out of the car? as it didn't show up on the analysis performed by Northwest Eurosport.

Can this $750 unit be repaired instead of replaced? and if so,can anyone recommend a source for repair?

All advise welcomed. Colin.

[David C Klasse]

See if any codes are stored in the unit.

1. Turn car on.
2. Set climate control to LO
3. Press and hold Rest and Defrost simultaneously until a new menu appears (about 5 seconds), should read DIA.
4. Using the auto button (not sure which one on your car) you can scroll through the diff numbered codes. Write the codes down and report them back here.

I just learned of this little trick the other day. It worked on my 1995 C280... but I tried it this evening on a 1999 E430 and could not get it to work. Give it a try and see what you come up with though.

I'll check the CLK and see if I can get it working on that.
Good luck!

[Colin]

Hi David,
This morning I hooked the operating unit up and checked this out, (holding the rest and defrost buttons simultaneously) but nothing, I performed this check both with the car running and stopped with key installed.
Though It sure would have been nice if the operating unit had it own self diagnostic ability.

Can you suggest anything else ?

Has anyone had to have one of these units repaired ? or are they simply thrown away and a new one installed ?

Thanks for you reply David.

[David C Klasse]

Colin,
Alright I did some investigating and found out that it will not work with the car on. You must have the key in the On position (ignition position # 2), but the car cannot be on. Try that and see what you come up with... let me know!

[Colin]

David,
I tried this theory again with the key in every position with the exception of running but no "DIA" display, I also tried a number of different button combinations asides of Defrost and Rest, infact I tried every combination common to rest and everything common to Defrost but still nothing leading me to codes.

I am begining to suspect that the rest function could be what is causing the battery to drain as rest is susposed to allow you to recieve heat from the engine compartment for a limited period with the keys removed, it appears to me that because of the continuios clicking (activation) of the Mono heat valve under the hood that the rest function is running all of the time and refusing to go off, hence not allowing me to run the self Diagnostic.

I know that if I take the car in to the Mercedes dealership they will recommend replacing the in dash operating unit, I will do some asking around for recommendations for specialized auto electronic shops that might be willing to repair the unit.

Thanks for all of your effort on this one.
Colin

[David C Klasse]

Yes, when I have REST on I can hear it click every few seconds. THat seems to be your problem, but is the Rest light illuminating.. or does the PBU let you know that it's on? Does heat come into the cabin also?

Interesting... I don't know why the DIA is not working on your car... I got the info from a 96 202, and that climate control is more similar to yours (maybe just aesthetically). Steve... can you help us out with this??

[stevebfl]

I placed the link to my diagnostic article in another thread. In it the fault code recovery is described for your exact car a 97 E320. The method is as follows:

"The procedures for pulling Fault Codes go like this (See Chart 3): Turn on the ignition, and set the left temperature to "HI" and the right temperature to "LO." Then, simultaneously press buttons "Rest" and "EC" for five or more seconds. All of this must be done within 20 seconds. The "Recirculate" button will flash its LED. The screen will then go blank, and the first code can be brought up by pressing the right "AUTO" button."

The rest of the article can be seen at:

http://www.babcox.com/editorial/ic/ic40142.htm

As to where to find a good rebuilt pushbutton controller, try Beckman Technologies. They are located in North Carolina. Being at home I don't have their number.

[Colin]

Hi David & Steve,
You guy's are great, I followed the Instructions by setting the Left side to Hi and Right side to Lo and similtaneously pushing the EC & Rest buttons for 5 seconds and bingo!! The Recirculate air button began to flash, the screen went blank and I was able to bring up the following codes by pressing the right auto button.

Eb 417 Eb 232
Eb 418 Eb 233
Eb 226 Eb 234
Eb 228 Eb 417
Eb 229 Eb 418
Eb 230 Eb FF

At this moment I am attempting to figure out what these codes translate to, I'm assuming they are all error codes.

Do these codes mean anything to you guy's, or should I pose that question another way, being that there are so many errors should I write it off and go in persuit of a re-manufactured unit, perhaps through Beckman Technologies.

Thanks Once again guys, you've made my evening.

[David C Klasse]

Colin,
Glad to help! WE really should be thanking Steve though, for he's taught me everything I know on this matter!
I have a few codes too...
They are:

#20: Evaporator temp sensor (B10/6) short circuit - with a footnote - intermittent Code 19 is continuous

#60: A/C compressor electromagnetic clutch (A9k1) - also footnote - intermittent

#80: Switchover valve block (Y11/3), tempering flap - also footnoted - intermittent

#82: Switchover valve block (Y11/3), tempering flap short or open circuit - intermittent


Steve gave me the meanings to all of these. I am not really sure of what exactly they mean. But I do notive how the word INTERMITTENT comes up at the end of every explanation, thus leading me to believe that they were random problems that did not occur over and over again. I have since deleted the codes and I'm going to see if any ot them come back.

Sorry, back to your problem, your car is now 4 years old... I wouldn't worry about 12 codes in the system, the likelihood is that they were one or two times recurring. Maybe just random problems, most of them anyway. Though I could be wrong. Now that you have the codes, try deleting all of them and then see which ones recur. I believe doing this will help us narrow down your current problem. Good luck and keep us posted!
And as always, thanks again Steve, you've been so good to all of us. We all appreciate it very much.

[stevebfl]

Your entirely welcome. It sure is cool that something I find so entertaining also provides a benefit.

As to the codes, If you go to the article and view chart #3, you will get the answer as to the basic code meaning. I did this and of course your numbers don't work. I presume you have misidentified them. It is pretty easy and is why in the text I give an example and a picture of the way a code B1234. First the code system has been standardized and "B" stands for body in the same since as Emissions codes start with "P" for powertrain. Due to the way the display is made the the full code will be split with three characters on the left and three on the right. The code B1234 was given as an example (sun sensor - almost always a code). It looked like this: Eb1 234. The E standing for error and the b in the lower case with the first diget of the code on the left; so the code is B1234.

I presume there should be a "1" placed in front of each of the numbers listed in your post.

I wouldn't worry about any of those codes. It is common for the car to accumulate such codes over time. I imagine they have been accumulating since new. Delete them and check periodically. I would not worry about codes if there are no symptoms.

Actually I just reread your post and was about to give this comment but it really applies here. I was going to state that most codes come during momentary periods where the battery voltage drops below 9v. Since you had battery problems I believe that to be your code setter, maybe even the the source of the control problem...reboot it.

[Gilly]

Colin, Steve, and David:
Not to discourage Colin from trying out Steves advice of trying to delete the codes and hoping for the best, but with the control unit going into REST function by itself, there probably be no real "fix" of the problem until the push-button panel/control unit is replaced.
I've replaced a couple of these for this exact problem.
Gilly

[Colin]

Steve,
You're right, I missed typed the codes and they should have been Eb1 for all of the codes listed in the previous post.

I know that I am going to sound clueless here, but I am.
How do I re-boot the operating unit?? and how do I delete the Error codes??

[David C Klasse]

Colin,
When you scroll through the error codes, it should read ENd, once you have finished scrolling through them. Following end, should be dEL. You must push the Arrow Up (warmer temp) and the Arrow Down (cooler temp) simultaneously. I am not sure if it is the driver's side or the passenger's side on your car, because I only have a single mode climate control.

[Colin]

I was able to clear all of the codes on my first go around with the exception of Eb1 417 & Eb1 418
Then I hooked up the mono heat valve and searched for the two remaining codes (Eb 417 & Eb 418) but they were gone probably due to my reconnecting the valve, and the display read FF, I'm assumming that this means finished.
Upon completion of the above I am still hearing the operating unit intermittantly clicking every 5 seconds and likewise the mono heat valve under the hood. This clicking stops when I press the rest button but resumes when turning the rest of, the light on the rest button is of while the unit and valve are clicking and light goes on when rest is pushed on.

Steve and Dave, thank you so much for your patience and perseverance on this issue, and for the wealth of information on how the error codes are found and deleted on this unit.
Steve, the article in Importcar (April 2001) was fantastic, believe me when I tell you that I have a printed copy on file with the car papers.

Ok Gilly,
would you mind telling me were you go to buy your operating units?? Do you buy new or remanufactured?? I am searching for info on Beckman Technologies

[David C Klasse]

Then it seems as though those remaining 2 codes are your continuous problems. Isn't there another way to solve this without getting a whole new operating unit? Seems like there could be a cheaper, smaller fix.