DL4567

(duplicating from W211 AMG section as I don't think engine spec matters on this issue)

Hi Everyone,

I've had my 2007 E63 for 7 months now, and have done quite a bit of work/repairs/maintenance to it (big surprise, right? haha). Bought it with 85k miles.
After all the work, one thing that continues to be a problem is the erratic behavior from the interior blower fan.

When driving for a while, you won't even notice it's not blowing, until you realize it's getting a little stuffy in the car.
First thing you do is press some buttons --- fan speed up/down, auto/manual, turn the wheels directing the air, etc, and sometimes that works to get air blowing again, but most of the time it doesn't.

This was a problem from the beginning, so on the first round of repairs my mechanic replaced the blower motor and resistor. The problem prevailed. Then they changed the blower motor a 2nd time, and it was fine for a while, but now it's doing the exact same thing again.

What's weird is that it seems to be affected by car speed. When it's not working for a while, it'll come on for 2-3 seconds right as you're coming to a stop, AND/OR as you're accelerating away from a stop. Maybe 10mph either way. But then it immediately stops blowing again and continues to not work as you're driving.

Anyway, I'm planning on taking it to the mechanic again, but just wanted to see if anyone here might be able to point me in the right direction?

Thank you!

konigstiger

https://www.benzworld.org/threads/20...#post-18565565

NewShockerGuy

I ran into this issue and made a thread about it a while back and posted in a couple others...

I went through 3 blower motor regulators (All OEM and new) before my blower motor started working properly again. I swapped the blower motor itself with a new one twice and even attempted to change out the HVAC control panel. In the end I guess it was just being finicky about the blower motor regulator for some reason. I'm happy to report though that the blower is working on all/any settings and any position now. Where before it would work, then stop working and I would be like why is it stuffy... then to feel no air coming out anywhere.

When using STAR it did keep saying blower regulator error, but I thought that couldn't be the case after replacing it twice with new. I figured it was more to it.

-Nigel

DL4567

Thank you so much konigstiger and NewShockerGuy/Nigel.

Konigstiger - my mechanical and electrical diagnosing ability is pretty limited, but I appreciate the info you've provided. Will use it if determining the control unit might be the cause of the issue.

Nigel - oh wow, this is great! I googled the problem but it didn't point me to your threads. I searched your history and read through your posts about it -- yep sounds very much like the same problem. Thank you thank you I will try to replace the regulator/resistor and see what happens. That's something I've done on 2 other cars so is within my skills.

ptkacik

Curiously, mine sometimes stops blowing while driving, and then almost immediately starts back up again. Yes, I’ve replaced my resistors and the blower.

Since electronics normally works or does not, I wonder if it could be a loose connector. I pit crewed on a 24 hour of Daytona race team many years ago and we had a bad brain box. After the third one failed, with no more replacements, we put the first box back in. It ran just fine. Turned out to be a flaky connector.

If mine gets worse, I may crimp the resistor connectors a tiny bit.Then again, it could be the interior temp sensor telling it that it is at proper temp or maybe sending a ZERO signal.

Just a guess,
Peter

NewShockerGuy

Mine's acting up again...smh. seems like if I don't drive the car for a couple weeks then it happens. Before I could turn the air on no problem after replacement at any fan setting and it worked. Now it's doing the same behavior. I can set it to AUTO or whatever and nothing happens. Then all of a sudden it will spurt out some air then stop, then it is trying to ramp up and it does it for a quick second then stops. Then if I keep it where it's at, eventually it turns on and stays on for the entire drive...

I can't tell you how frustrating this is. I pull up STAR and it says the same error message with the blower regulator yet when I run through the diagnostics in star the blower motor runs perfectly fine. As I adjust the blower motor you can see the resistance change in STAR. Then when I unhook STAR to the car the blower motor acts weird again. I'm not sure why a blower regulator would keep doing this when it's an OEM genuine part. Makes me regret changing out the blower motor initially because of a small squeak noise. Ever since that I feel like it's been problems. Blower motor twice (both OEM genuine new parts), blow motor regulator 2-3 times (both OEM geunine, new).

It's like an overly complicated HVAC system...lol I've never experienced this in any vehicle I've ever owned before.

-Nigel

juanmor40

Sounds like a poor connection/contact somewhere.

Let us assume it is a poor/loose ground. I assume loose since it is intermittent; however, if it passes with STAR with the vehicle parked, and fails immediately after STAR is disconnected. I will discard the ground issue.

Then,
- Did you try STAR activating the AC different modes? All work?
- Did you try with STAR connected, but manually activating the different AC modes? That is not the same as with STAR disconnected and manually activating the AC.
- If the above works with STAR, but not manually I would follow with the AC command panel. Perhaps a bad contact in the module.

My 2c

NewShockerGuy

That's what I thought as well honestly. I think I checked the connections at least 5-6 times going back and forth on the regulator/blower motor and checking to see if there was anything loose or nicked...etc. All looked perfectly fine.

When I hook up STAR and have it run the the activating AC different modes, it all works fine. Zero issues. Shows on STAR the regulator load/%/resistance...etc. I can up the speed/down the speed and it follows.
If I stop the STAR activation and turn the fan speed up down manually it works. (Note that STAR is still connected/multiplexer still connected, but I'm manually adjusting the fan)

However when I disconnect everything and then say shut the car off and turn it back on then it will either not do anything or work.

Yesterday and today I tried something going to work. I had it on the coldest setting and when I pushed the fan button nothing was happening. If I turn the knobs all the way to hot then it starts to blow. If I then turn the knobs down to the coldest setting it stays on and I can press the AC button and it still blows cold air. It did this everytime. Then when I shut it off and turn back on it stays on. But if I start the car with it at it's coldest I don't get anything. Makes me want to believe perhaps it is something related to the HVAC control unit itself ... I bought a used one for testing purposes back months ago but I think it was defective because when I had it plugged in the AC light button would just flash and when I ran it through STAR to initialize it said the AC refrigerator was low. Which never happened with my original unit. I pulled out my HVAC gauges and hooked it up to the car and it was in fact not low at all. Then when I put my original HVAC panel back in it was all working again.

I just bought another one on ebay. This time the part numbers match up 100%.
My unit in the car reads:
211 830 3290
Q: 001 4508

The previous one I bought was:
211 830 3290
Q: 001 4708

Which the Q number should only be a updated version. But again without knowing 100% how it came out of the car or if in fact it was already damaged it's hard to say. I just know I never had the blinking AC light and still do not. I'm hoping now that the test one I'm getting from ebay via the same part number of my current one is in good condition. Looks to be, but internally who knows?

I can update when I get the hvac panel next week. I still love this car. But the hvac situation is annoying...lol. I'm hoping it is just the panel and that this resolves it. I can't imagine 2-3 blower fans and regulators to be bad. There has to be something else and the only thing I have not replaced is the HVAC panel.

-Nigel

Jay Blaze

I have 2006 cls500 70,000 miles on it. When i drive my ac blower turns on and off. I bought new blower motor resistor and blower motor from mercedes still and still does it. I noticed on hot humid days it does it all the time. In the morning it works normal. I thinking a sensor issue...could humidity sensor cause this? It also had a code 9103 and says communication fault of busc sensor..

DL4567

NewShockerGuy, thanks so much for the update. That's both good and bad news. Sorry to hear you're having trouble again but very interested to know what will happen with the new control unit.
Mine has actually been working ok since my last post (knock on wood and several other superstitious gestures), so I haven't been back to the mechanic with it so far. Nor am I in a hurry to do so as long as it's working decently, knowing it's so difficult to figure out.

Jay Blaze - interesting to hear from another person with the same issue, in a different model even. Seems that this isn't a terribly unique problem.

CaliBenzDriver

I've had my share of blower fan issues to know it's non-negociable during extreme temperatures.
✌️

it sounds like next thing to look at is the AAC Module or even better, something free and quick like a poor GND screw nearby ?

Is this list of spares accurate:

• new blower motor
• new ballast "resistor" module
• ....

If you though a scanner was expensive... now is the time to look at the HVAC controller fan speed data with your scanner.

Confirm the HVAC can command full speed with a scanner

Check live voltage and GND available at the motor with a DVM

Check condition of blower harness for burnt connectors. These fans can run tight and overdraw high current to cook female connectors.

A thermo-fuse protection is built-in the ballast speed control module... ie. power should be going through a new module, right?

Jay Blaze

i did scan ...only thing off is humidity was off

juanmor40

. You know where is located, right?

Bayrat

I am pretty sure that I have located the real issue on the intermittent blower issue. After removing the blower motor and unplugging it, bring it on a bench test with an ohm meter to test continuity ( the little speaker emblem on ohm setting),this will beep if you have continuity, or if you don’t have this feature, the ohm will read as 0.0 or similar. To note, my blower motor had stopped completely after working intermittently for awhile.
Take the motor out of its housing(two screws, make sue t keep the three plastic noise reducing pieces, you will see them). After setting your ohm meter to the proper setting, place one probe on + and the other on negative wires inside the fan plug. The meter should NOT beep as it is unlikely to have continuity (If it does beep showing continuity, stay with me as you may find out why it is intermittently having continuity. Now put one probe on the + side of the plug and the other where the positive wire is soldered to the post on the motor, you should get a beep for continuity. Do the same with the negative wire, if it beeps, your wires and plug are NOT the problem.
Now here is where you will find the problem. Look behind both the +and- posts and you will see that the wires continue past the soldered post and into a housing. In that housing, you will see a small spring that is held taught by a small metal clip on the outside of the housing. Both sides (+ and- are identical). Now ohm test the two wires behind each of their respective posts and you will likely get NO beep/continuity. Inside of each housing there is a small metal plate(shim) that crimps the wire to the motor with the pressure of the spring. If you jiggle the spring and shim with your ohm probes, you should start getting the meter to beep. That’s where the intermittent or zero continuity is occurring.
Once you figure which side that the spring is not holding the shive tight against the wire, remove the metal keeper off the end of the spring housing, being careful not to let the little spring shoot out. Now put the spring back in against the shim where it is straight and applying maximum pressure and reinstall the clip on the end of the housing. You should now be able to get a beep/continuity between the two wires behind the +and- soldered posts, as well as between the two houng spring keeper plates on +and- sides of the motor.If so, you should also now have continuity/ beep when testing the + and - sides of your motor plug connector.
If this works. Don’t immediately install fan until you plug it in on your floorboard, start your car and hit it with max power (front defrost). That will put max movement on the springs. If it continues to work, run it through all the settings and they should work. If so, reinstall under dash.
This is far less complicated than it sounds. Hope it helps anyone with this problem, it cured mine…for now….it is a Mercedes.
​​

NewShockerGuy

Appreciate the information. So this is done on the FAN housing assembly itself? I just want to make sure I am tracking, it's sometimes harder to follow without pictures being posted... I've replaced the blower motor now 3 times and if the spring is located on the blower motor assembly what is the chances of the spring being loose on new units that many times?

I'm going to check it out this weekend.

Thanks,
-Nigel

Bayrat

The sprins that hold the brushes against the motor are in the motor itself.
If your fan motor is a aftermarket replacement, it could very well have the same problem's.

take the motor out of the large plastic white fan housing by unscrewing the motor and disconnecting the plug that is attached to the resistor that is attached to the housing by one screw. That is the plug to start testing for continuity. If it has continuity at the plug, my issue is not yours. If it has no continuity, test continuity of both the positive and negative side of the plug to the respective post that the are soldered to in the sides of the motor. You should find that they do have continuity. Follow the wire from the post on to the brush housing. (Black plastic housing attached to motor). If you have continuity from plug to brushes and not both sides of the plug, the circuit is broken between the two brushes thru the motor.
I fixed mine several times only for it to continue to fail. I have replaced it with a much better built 3rd party fan motor with no issues since. I’ll send pictures of the good one and the bad one soonest.
The spring and brush would not stay pressed on the copper motor over time, causing continuous loss of continuity over time.

Bayrat

2012 s550 well built aftermarket blower replacement