Blower fan problems
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Joined: May 2024
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E250 CDI W212 2014
Blower fan problems
Hi all, having an odd problem with my blower fan, hoping someone can help.
I had the AC on full power and the fan suddenly cut out. Did some research and decided to replace the resistor unit, the fan still didn't work. Removed the fan and tested with a 12v source, didn't work so got a replacement fan. Now the fan comes on when the ignition/engine is on and speed increases/decreases as expected. The problem now is that the fan cuts out after about 30 seconds then restarts. It goes through this on/off cycle a number of times then goes off completely. If I turn the engine off and on again the cycle restarts.
I'm stumped, possibly a defective resistor? Grateful for any thoughts.
I had the AC on full power and the fan suddenly cut out. Did some research and decided to replace the resistor unit, the fan still didn't work. Removed the fan and tested with a 12v source, didn't work so got a replacement fan. Now the fan comes on when the ignition/engine is on and speed increases/decreases as expected. The problem now is that the fan cuts out after about 30 seconds then restarts. It goes through this on/off cycle a number of times then goes off completely. If I turn the engine off and on again the cycle restarts.
I'm stumped, possibly a defective resistor? Grateful for any thoughts.
Out Of Control!!
Joined: Apr 2019
Posts: 11,811
Likes: 6,705
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
new cabin blower... still quits spinning
You've replaced both your cabin blower + ballast resistor module with next to no improvement.
-- You may want to use an OBDII scanner to read your AAC Module data... all temperatures sensors are listed with fresh numbers.
-- What is the chassis voltage when the fan gets disabled... above or below 13Volts??
-- How old is your cabin filter?
Without sufficient air flow the electronic ballast may simply cutout due to overheat protection.
Remove cabin filter to test for unrestricted air flow.
Hope this helps you figure out a solution.
-- You may want to use an OBDII scanner to read your AAC Module data... all temperatures sensors are listed with fresh numbers.
-- What is the chassis voltage when the fan gets disabled... above or below 13Volts??
-- How old is your cabin filter?
Without sufficient air flow the electronic ballast may simply cutout due to overheat protection.
Remove cabin filter to test for unrestricted air flow.
Hope this helps you figure out a solution.
