W212 2012 Heater/Interior Fan Does not Work
MB E-350, W212, 2012. I would appreciate any help.




How do you know heat and AC are working? Have you removed the intake cowl to view the fan to check on it from above?
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I found my fuse map in the trunk folded up in the tool kit. Here......
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thanks though! Hopefully it helps someone. We need to keep this forum strong with this type content!
So is this a warning that tells me I should replace that fan before it stops working for good?
I'm getting two different parts for the blower mower resistor. Both are about as expensive as the blower motor itself. Rock auto shows two very different pictures:
I still have varying fan speeds so I'm going to leave that until it fails. Just to be sure - These are just resistors that "fail open" so any issues with this regulator won't harm the motor. I don't want to damage a new motor because I should have replaced this regulator. Thoughts?
Last edited by RWagz; Jul 29, 2023 at 04:49 PM.




I don't think the fancy ballast is involved in killing the fan. More like the fan overheats the ballast cooked without proper air flow (plugged cabin filter!!)
Here is the facelift ballast for ya...
Great unit in contrast with the defective fans.
cabin blower controller
heatsink area
Last edited by CaliBenzDriver; Jul 29, 2023 at 05:19 PM.
Did you find any instructions on how to replace it that you can share with us?
Please?
Removed it by gently holding a narrow screwdriver tip against the commutator while manually spinning the motor. Carefully used a knife point to ensure no shorts between the the commutator connections (the shiny copper bars of the commutator), then blew all the dust out. Yup, a pretty awful backyard mechanic repair - but it worked to save me quite a few dollars, plus I learned something.
Works great now, but I imagine I'll have to replace it next year.
Just remember if using flammable cleaners to ensure that the motor is COMPLETELY DRIED OF THE CLEANER before reinstalling the motor.
So is this a warning that tells me I should replace that fan before it stops working for good?
I'm getting two different parts for the blower mower resistor. Both are about as expensive as the blower motor itself. Rock auto shows two very different pictures:
I still have varying fan speeds so I'm going to leave that until it fails. Just to be sure - These are just resistors that "fail open" so any issues with this regulator won't harm the motor. I don't want to damage a new motor because I should have replaced this regulator. Thoughts?
Most of the repairs I've done, the blower actually would blow as intended, but was pulling 5 to 10 amps too much for the resistor to live very long. For this reason I would replace both blower motor and resistor to ensure proper operation of system and amp draw.
As for which blower control, you need your build sheet with codes for your car, The top one in your picture is for cars with (code 800) for the climate control system.
But this is based on the work I've done using proper testing equipment, technical data, and schematics to guide me. Your mileage may vary.







