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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