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I recently discovered a squealing/cricket noise coming from the passenger seat footwell. It got louder over time and eventually I narrowed it down to a bad blower motor. I replaced it and the sound went away. Along with the sound, I noticed weak airflow - even on the highest fan speed. I thought replacing the blower motor would resolve this. It did not. The same day I went out and replaced the cabin air filter. Same weak flow. What could be wrong? Before it used to feel as if the windows were down that’s how hard it was blowing.
I recently discovered a squealing/cricket noise coming from the passenger seat footwell. It got louder over time and eventually I narrowed it down to a bad blower motor. I replaced it and the sound went away. Along with the sound, I noticed weak airflow - even on the highest fan speed. I thought replacing the blower motor would resolve this. It did not. The same day I went out and replaced the cabin air filter. Same weak flow. What could be wrong? Before it used to feel as if the windows were down that’s how hard it was blowing.
Hook up a scanner to check for flap actuator codes in your A/C module.
Standard HVAC flap actuator
solderless pins feeding motor + module
Solder + grease for normal life span
Can you manually raise the blower speed to supersonic speeds -or is the "regulator" stuck on a default low speed ?
Try removing the filter to compare the flow with/without ... aftermarket quality may restrict flow.
Old fan sleeve bearings may only need 2 drops of oil, reinstall to compare speed with replacement unit.
Last edited by CaliBenzDriver; Jul 7, 2022 at 05:23 PM.
Hook up a scanner to check for flap actuator codes in your A/C module.
Can you manually raise the blower speed to supersonic speeds -or is the "regulator" stuck on a default low speed ?
Try removing the filter to compare the flow with/without ... aftermarket quality may restrict flow.
Old fan sleeve bearings may only need 2 drops of oil, reinstall to compare speed with replacement unit.
Thank you for your reply. The fan speed changes but will only go up to a certain point. After the third level or so you can’t feel a change. I will try all of this. I am also replacing the regulator/resistor.
this is the microcontrolled regulator in charge of driving the blower speed. As good as it can be. power electronic control
Pretty honest quality overall. The main draw back for owners is this module gets showered by rain penetrations as evidenced by heavy aluminum oxidation. Fixing that is going to be not simple.
Dang.... Cali you have autopsy you HVAC flap control unit too ?
How much of the dashboard need to be dismantled to reach that..?.. OMG
It's not easy just pull the steering column and the glove box to gain access to all 5 actuators... they are all identicals units in case one gets worned out.
While your fixing your stack of solderless steering modules, the dummy ignition switch nearby needs attention as well.
The outcome of that rework is now my electric steering tracks straight on the Hwy instead not pegged on 0° center. This car was ridiculously unstable courtesy of funky electronics. A normal function of electric steering is to be heavy around 0° to hold straight. It's really nice to drive when the car is planted straight on the Hwy!
The only thing missing now on my list arethe 3 radars in front bumper skin
the LED HL drivers modules
the clunky LIN windshield wiper motor
2x hard to reach painted GND posts
I am really curious to see how MB engineers managed to get my blower regulator soaked so rapidly... (no leaves plugging my conduits, EPDM outlet rubber not melted shut...)
I'd like to inspect the driver side rain channel to prevent soaking my F-SAM at any rate.
I dont know if W212 way of sealing rain water is the same as this W204 C300, for the HVAC blower, mine is okey so far no air gap or sealant failure...yet.
But this area one day need to be re-sealed before actual sealant failure can occur, and silicone is not good for that.
Some marine sealants are very good for such sealing work, mainly polyurethane https://multimedia.3m.com/mws/media/...s-sealants.pdf
The front SAM as you know is straight forward. Rubber like gasket on the Front SAM white container box and direct to fire wall. https://www.ebay.com/itm/233627718060
Aha... this is the plastic component responsible for watertight-ness of the removeable air box above battery to firewall....which is for HVAC blower air path. Item 100. This is from a RHD car. https://www.ebay.co.uk/itm/263726847453
Above device item 100 (RHD car ) is also rain water collector from the big plastic tray/cowling of windshield, where the 2 wiper shaft pops out.
This tray, item 10 : https://www.ebay.com/itm/265579543292
Item 100 (RHD car ), So it is the same o-ring seal like front SAM fuse box white housing to firewall.
We must also make sure the grey foam seal at the air intake box item 50 is still good.
Mine, at 1 region got small cut, because I have opened this air intake box like 100+ times ha ha ha https://www.ebay.com/itm/254364519243
Last edited by S-Prihadi; Jul 10, 2022 at 06:58 AM.
Reason: add info
thank you Surya for your parts research. One of these plastic piece helps channel water where it shouldn't.
Let me know when you need help with your steering column, it's a lot of fun to play with.
Last edited by CaliBenzDriver; Jul 10, 2022 at 12:51 PM.
I wasn’t getting no air flow either, in winter very little now summer out AC on and nothing comes out, very rare would the AC blower turn on randomly then after a min shut off again I just ordered the resistor I hope that is the issue it gets to hot in that car
Removal and replacement is so easy with this part. Right off the bat I noticed a huge difference in fan speed. I have my original strength back! But now I’m experiencing a different problem. The air is lukewarm! The best I can describe is that it feels like the lowest heat setting but actually the A/C is on at the lowest setting and highest fan speed. It had the cabin fogging up and me sweating. I don’t know what’s worse: poor fan speed and airflow or super high fan speed and basically heat hitting your face. I’ve decided it might be time to take it to my local shop.
Note: I used an aftermarket resistor part from O’Reilly. I’m debating whether I should return it and buy OEM, in hopes that it’s just a crappy part.
What year is your car? Could most definitely be low freon, go to auto part store and buy freon it’s very easy to put in, I bet that’s the issue with the warm air
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