Please help me. I'm a single female who knows NOTHING about cars. Background, I have a 99 C280 Benz. I recently had to replace the A/C temperature control panel. I was so happy because I had air again (I'm in Texas, so you can imagine how happy I was). Anyway, immediately after the mechanic replaced the A/C control panel, I noticed that my car sounded like an airplane about to take off. The fan was extremely loud. I asked the mechanic about it and he said, well it's hot so the fan is going to be operating full force and I'm thinking okay, I've been without air for a year, so maybe I've forgotten how my car use to sound when the a/c was working. But, even after I turn the A/C off, the fan is still loud.
I took it back to the mechanic and he said the the auxiliary fan control module needs to be replaced.

So, my question is this: is it just a conicidence that this part went out at the SAME time that they replaced my temperature control panel? I mean I brought the car in that morning, the fan was working fine, picked the car up a lilttle while later and the fan is operating on high.

Please explain it to me as though I were a 2 year old

P.S. I'm new to the forum, so I hope I've posted this correctly.

Welcome aboard. NONE of the single guys crawled over this post?? Sheeesh, they're slipping.....
The fan would seem noisy at high speed, true.
If the fan module fails, usually the problem is NO fan operation, not high speed. We'll have to trust the technician is correct, BUT if it does the same thing after replacing it, make sure he doesn't bill you for the part! Are you sure the fan was running fast, which is why it was noisy? Or was it just possibly caused by the fan not being operated for potentially 1 year or so? But I agree, a auxillary fan operating at high speed=airplane-ish sorta noises. Also the higher fan speeds are typically called upon by high engine temps, not by the A/C system, but again you/me/we are at the mercy of the diagnosing technician now. Yes, it seems odd that the fan decided to act up after the AC panel was replaced. But if the old panel never called for the aux fan to run, and now it is operating properly and switching on the fans, but the controller is messed up (high speed only), sure maybe you never noticed it. I'd go with it for now, see what develops next. Now don't get to cozy with all these single guys at this site. Sharks, sharks I tell you, to the last man!
Gilly

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I appreciate you responding to my cry. All i know is now whenever i turn my car on, i can hear that blower operating on high regardless if the a/c is on or off

i'll let you know what happens when i get it repaired.

ciao

The mechanic probably could have taken the initiative to disconnect the fans for now, assuming it'll be less than a week for the part to arrive, with instructions on how to plug them back in if the gauge starts reading too high. But then again this is just the aux fan, so the engine fan should keep the engine from overheating, except maybe in a bad traffic jam on a really hot day.
Gilly

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Disconnecting the auxiliary fan is definitely not fine if you plan to run the air conditioner. It needs the extra fan action when you slow down.

I don't know how the controller works on that car. On my early ('96) 210, if the fan controller fails in full-on mode (by one of the MOSFETs going to full-conductance), the fan will run all the time, even with the key removed. My fan control module (N65) is controlled directly by N22, so if I had this problem, I'd suspect N22 rather than N65. Later 210's use a completely different set of parts, including the (rather expensive) N10-1 in the fan control path. But of course, few if any of the prior part designations apply to your car.

Please note: I'm not one of these "single guys" crawling over this posting, but rather quite happily attached.

The AC will work better than it did before the control panel was replaced. Either way is fine, I'm just "arm chair mechanic-ing" anyways.
Gilly

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i was feeling kind of down, but after reading your responses, I had to chuckle a little bit. You all have a great sense of humor. But anyway, I won't be able to get it repaired until after the 5th, but on the upside, my a/c works great. I wonder why the mechanic couldn't hear how loud the fan or blower or whatever it's called, was sounding when he replaced the temperature control panel?

Lastly, why didn't i have this problem with the fan when my a/c wasn't working - i hope that's not a stupid question

goodnight all

I have the exact same problem on my recently acquired 2000 C230 Kompressor sport. I've done some troubleshooting/research on the aux fan control scheme used in these cars and it seems that the Climate Control module (N19 or N22) is responsible for generating a signal to activate the auxiliary fans. I've also discovered that if the climate control panel is replaced it must be "version coded" using a special software application that typically resides at, you guessed it, the local Mercedes-Benz dealer. There are several posts in the archives about aux fans not working properly due to incorrect "version coding" of climate control modules. Ask your mechanic if they set and verified the version coding of the climate control module (Module N19 or N22) when it was replaced.

I'm not exactly sure what "version coding" is but I'd guess it is used to set-up control/information parameters, protocols and features that are specific to a particular vehicles hardware and software systems. Kind of like getting the right printer driver for your specific hardware/software environment.

WOW i just didn't realize how complicated these cars are - it seems to me, I'd be better of by biting the bullet and taking my car to the dealership (oh horror) to get it fixed PROPERLY. These Benz's are like women: expensive, tempermental and there's always more than meets the eye

thanks so much for your detailed response. i think you really may be on to something cause it's just mighty funny how my fan was sounding normal until he replaced the climate control panel. How long did it take you to research - man, i'm really impressed.

Tim
Yes you are correct on version coding. The same modules can be used on several different models. In this case, maybe you've noticed the climate control panels between a W202 C Class and W210 E Class are usually virtually identical, then you throw into the mix that cars will vary from country to country, yeah sometimes on a global scale the part you are buying could be used in either model, depends on where in the world you are. SO, someone needs to go into the control module with the computer and select which model the new control module is being used in. To expand just a bit, about the only difference in the climate control panel in the USA between the 210 and 202 is in the USA the 210 has charcoal filter, so yes there IS a difference, but in another country the 210 may not have charcoal filter, at least as a standard feature, so the control panel may be the same as the USA 202. Heck in some countries, believe it or not, air conditioning is even an option!
Gilly

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Thanks much Dan - It is hard to believe that A/C is an option nowadays.

Can version coding be verified/set with any of the aftermarket scan tools? All the documentation on Star Tech mentions the HHT as the needed tool. I hate to go to the dealer for something, for some reason it just feels like I've been defeated if I have to resort to dealer help.

My wife is now driving an 98 E300D and I recently "upgraded" to a C230 Kompressor - prior to these cars my daily driver was a 91 300D. I've recently purchased the CD and DVD's for my newer cars and I've got to say I'm stunned at the level of computerization in these newer models. You can't turn on the lights, adjust the rear view mirrors, turn on the wipers, adjust the seats or even use the turn signals without involving a computer. Everything is networked together and after seeing the level of automation I'm amazed the newer cars are as reliable as they are.

I still have my 91 300D and while the C230 Kompressor is a very nice ride I'm not sure I'm going to keep it. It scares me.

I don't know about N19, but N22 can be version coded either through the HHT or through its own keys.

On the 210, N22 does control the auxiliary fan, but how it does so varies by year or updates to the car. There are at least three different means of using the generated signal to start the fan (N65, N65/1, and N10-1 plus N76, IIRC).

Yeah I forgot about doing it through the control panel itself. Because I have a dealer background I forget about those things. As far as using a non OEM scanner to do it, I think some are better than others. The info falls under what is called "proprietary info", MB doesn't have to release this info if they don't want to, the "OBD" codes are the only thing they are obligated to release, although many manufacturers are releasing this info fairly soon aftetr the bugs are all worked out, takes a few years. They kinda realize that the dealerships would be overwhelmed if the aftermarket couldn't be allowed access to the various systems, they almost NEED the independents to work on them after the cars are over a few years old.
Gilly

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I think they expect the independants to get the Star system. As far as I am aware, nothing but powertrain codes are available through the ODB-II port for my '96 210.