I broke down and took the car into the dealer for them to check the ACC version coding with their SDS. According to the dealer my version coding is correct - their diagnosis is a bad instrument cluster. I guess this is plausible since the climate control module does receive engine temperature information via the K1 serial interface. Maybe N19 is not getting engine temp information from the instrument cluster and responds in a default manner by activating the fans at 100% speed?

My dealer wants $1,000 to replace and recode the instrument cluster.....

And if that's not bad enough for you as I'm driving to the dealer I notice the car is feeling a bit sluggish. I proceed to do a couple of full throttle acceleration runs and the car is now severely hesitating/surging at anything more than 50% accelerator pedal travel - no check engine lights are on.

I've only owned this damn thing for a month and I'm already loosing interest in forming any sort of long-term relationship.

Sounds like a mass airflow sensor...........damn, what luck
Gilly

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My car had a stored P0170 code and the fuel adaptation at part load was 1.27 - which as I understand it is just below the threshold for a check-engine light. A new AMM solved my problem and the car is running better than ever.

Aux fans are still a problem - I'll post the final fix for that one after I figure out whats wrong.

YOU ROCK DUDE I just had to thank you once again for sharing your findings with me. I took my car back to the mechanic and asked about the version coding and he never did say whether or not he did that or not. He looked very irate and told me to leave my car and he'd take a look at it. Bottomline, when I picked my car up that evening, my fan motor was sounding normal.

Because of you, I saved $356 dollars. Thank you, thank you, thank you, you really came through!!!

And now a final report....

The dealer replaced the instrument cluster and it did not fix the problem. They reinstalled my old cluster and suggested changing N19 as the next step. I purchased a used climate control cluster from PGA and installed it with my old cluster - no change.

The dealer then installed the new cluster with the "new" N19 module from PGA and the fans now work normally. So it would appear that the cluster and N19 were not exchanging engine temp information via the K1 interface.

On my 2000 C280, the fan is not an auxiliary fan - it is the ONLY fan. It is mounted behind the radiator, there is no engine driven fan.

I had trouble with my A/C losing capacity at idle - as in traffic. There was a bad socket in the plug connection at the engine module (can't recall the N#). There is also a control module inside the lower fender liner of the right front wheel well. Incidently, I never "hear" my fan run - it cools well enough at low fan RPM so it doesn't generate much noise.

The later W202 is entirely different than the early W202. I have a 1995 C280 - it has an engine driven fan and two electric auxiliary fans in fron of the radiator. The controls for the fans are entirely different also.

if i remem correctly one[yes one] climate control panel fits 3 cars c,e,and sl and a set of instructions comes with new panel so that it can be set for whichever car its being mounted to.if you dont do it right one of the symptoms is full aux fan all the time.

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David S Poole
European Performance
Dallas, TX
4696880422

"Fortune favors the prepared mind"
1987 Mercedes Benz 420SEL
1988 Mercedes Benz 300TE (With new evaporator)
2000 Mercedes Benz C280
http://www.w108.org/gallery/albums/A...1159.thumb.jpg

The panel for the C-Class is different than in the E-Class. The E-Class panel is designed to control dual zones (i.e. left & right), the C-Class is not.

In addition the ACC panel for the 4 cylinder W202's for the 99-00 model years are TOTALLY different than the ones used on the 6 cylinder W202's in the same year. There are also about 5 different schemes used to control the Aux fans depending on your year, chassis and equipment level. It all seems like an absurdly complicated way to manage the functions of the aux fan system.

They can save alot of weight in wiring by having the fan control module controlled by the engine control module, which is monitoring engine temp at all times, and the climate control system which keeps track of the pressure in the AC system. Not all that complicated at all, although the engine control module is sharing info with the instrument cluster for the gauge, which adds just a slight kink in it, but I wouldn't consider the system overly complex or difficult to understand. SOMETIMES it's difficult to decide which component is at fault when there is a failure. A tech with good diagnostic equipment can fairly easily diagnose a bad fan control module (or fan) by entering in to the climate control system and raising/lowering the fan spped to see if it responds. If not you can jump batt power to the fan and see if the fan is capable of running high speed with direct battery power, which of course corresponds to 100% fan speed.
I agree about the control panel needing to be version coded to the chassis number that it's in. Even though the control panel may not be correct in that chassis in a US spec vehicle, it may be correct in a different country. Remember, when confused on exactly why they decided to use different control types in different engine configurations, etc, that it really is MBUSA that makes these decisions on what they want Daimler-Chrysler to build for the US market. Within reason anyways, DC can tell MBUSA to go to Hades if they have a stupid request. But yeah, for all we know MB would have been happy to build the US a C300 Turbodiesel with 6 speed manual, if MBUSA thought they could sell enough of them to make it worth all the emissions tests etc to certify the car. WOW I made that up right now, doesn't that sound neat, C300 Turbodiesel...........
Gilly

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Click here to see the items I have up for auction at EBay

Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold)