Climate Blower Motor Turns On After Car is Shut Off
#26
Super Member
Joined: Jul 2016
Posts: 529
Likes: 103
From: NE OHIO
1998 SL500,2011 GL550,2009 ML350,past 1995 E320 Cabrio ,2005 ML500,2006 ML500,1996 SL500,1972 280SEL
12 volts constant .
There is 12volts running to the fan control board. Drop the fan and unplug the wiring . remove the cover and use electrical contact type cleaner and remove all the corrosion … that should fix it.
#28
I did the same thing srtdc. It fixed my problem as well.
The real question is how did all of that moisture build up inside the coated, sealed resistor cover so I can prevent reoccurrence?
The real question is how did all of that moisture build up inside the coated, sealed resistor cover so I can prevent reoccurrence?
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Dinismb (11-28-2022)
#29
Great...happy for you. I'll bet the the metal nut holding the plastic squirrel cage has rust. I saw all the used ones on EBay also had the rust.
Its a design issue. The vent in the hood allows rain/snow/water in and the blower sucks it in and throws it into the board. If you open the housing on the fire wall (just 2 clips- easy)
you can see the path via the hole on the bottom.
Mine is a 2008 - 14 years old. Cleaning the contacts every 14 years isn't bad, I'll live with it. Or, you could put a sponge in the hole to absorb any water...LOL
BTW: I think the fuse for the blower is next to the battery...another stroke of genius...
Its a design issue. The vent in the hood allows rain/snow/water in and the blower sucks it in and throws it into the board. If you open the housing on the fire wall (just 2 clips- easy)
you can see the path via the hole on the bottom.
Mine is a 2008 - 14 years old. Cleaning the contacts every 14 years isn't bad, I'll live with it. Or, you could put a sponge in the hole to absorb any water...LOL
BTW: I think the fuse for the blower is next to the battery...another stroke of genius...
The following 3 users liked this post by srtdc:
#30
I had this exact issue with my 2007 GL450. The blower motor would run continuously after the vehicle is shut down and locked. The wealth of information here is amazing. I was able to follow the instructions found here and successfully cleaned the blower motor circuit board, and everything now runs as it should.
Many thanks to all who share their experiences here.
Many thanks to all who share their experiences here.
The following users liked this post:
Dinismb (11-28-2022)
#31
*CONFIRMED FIX* on 2008 ML350! i had this issue happen to me in 2023, so wanted to add my story as well- as this can still happen to the w164 even in '23! here's a brief synopsis of what was happening on my w164- every once in a while the battery would randomly die overnight or after sitting for awhile, i just chalked that up to some odd anomaly that i would need to keep an eye on. however by february of 2023- i had noticed the HVAC blower motor would stay on after i turned the key off. while i did read one thread comment that said MB does this to avoid moisture build up in blower ducts, and of course theres the "REST" feature... this was clearly neither of those as the blower motor would just run constantly until the battery was dead.
thanks to this thread, i was able to diagnose and solve this very weird problem. i HATE electrical issues on cars, as they can be a nightmare to trace down.
as other users have pointed out, what ends up happening is that water from carwashes/rain/snow/etc will fall into the hood vent and drip down into the drain channel. most of it will drain as needed, but some water may get by (esp if the drain becomes plugged) and will seep into the blower motor where it will rust out the main center bearing and drip down through it and get into the bottom where the circuit board is, and short it all out- causing the fan to have a mind of its own.
i have attached a pic of my stock blower and the replacement from ebay, you can see the design revisions as well as the rusted out center bearing on the old fan on the left. especially of note, notice how the old blower on the left has HUGE openings that can easily allow water into the core of the motor. the new one is sealed up tight like an umbrella. i suspect this will be a much better design.
the new part was 100 bucks on ebay, and appears to be a revised version of the stock Siemens blower that came on the car. i suspect this revised blower motor may not have this annoying issue, but i will report back if anything comes up in the future.
the fix was not too bad, the hardest part was unplugging the old fan plugs (2 of them) in february with cold fingers on a garage floor. one plug has two clips on each side, the other one may require a small screwdriver to help you move the clip on the side. but once you get the old fan out (4 torx bolts) after dropping the panel below the glovebox (also 4 torx - same as the fan) the old unit comes right out and the new one fits perfectly - and thanks to MB desiging a pro socket, you dont need to worry about bolt alignment as they all self-locate making it much easier to work since the repair is done all by feel rather than by vision.
tested the new blower motor these last 2 weeks, in all AC and HEAT modes, AUTO and MANUAL, and everything works great. PLUS the new blower has an audible "power down" about 1-2 seconds after you shut the car off, meaning its very obvious that you HEAR a power down (and thankfully never a power UP meaning i no longer have to worry about something running all night when i dont want it to and waking up with a car that wont start.
just want to thank everyone in this wonderful thread for the great information and wisdom on the root cause of this weird electrical issue. i wanted to add my experience as well, in the event it can help some future w164 owners. this is also a great time to change out both cabin air filters as well!
huge shoutout as well to @srtdc for their knowledge and wisdom on the underlying cause!
thanks to this thread, i was able to diagnose and solve this very weird problem. i HATE electrical issues on cars, as they can be a nightmare to trace down.
as other users have pointed out, what ends up happening is that water from carwashes/rain/snow/etc will fall into the hood vent and drip down into the drain channel. most of it will drain as needed, but some water may get by (esp if the drain becomes plugged) and will seep into the blower motor where it will rust out the main center bearing and drip down through it and get into the bottom where the circuit board is, and short it all out- causing the fan to have a mind of its own.
i have attached a pic of my stock blower and the replacement from ebay, you can see the design revisions as well as the rusted out center bearing on the old fan on the left. especially of note, notice how the old blower on the left has HUGE openings that can easily allow water into the core of the motor. the new one is sealed up tight like an umbrella. i suspect this will be a much better design.
the new part was 100 bucks on ebay, and appears to be a revised version of the stock Siemens blower that came on the car. i suspect this revised blower motor may not have this annoying issue, but i will report back if anything comes up in the future.
the fix was not too bad, the hardest part was unplugging the old fan plugs (2 of them) in february with cold fingers on a garage floor. one plug has two clips on each side, the other one may require a small screwdriver to help you move the clip on the side. but once you get the old fan out (4 torx bolts) after dropping the panel below the glovebox (also 4 torx - same as the fan) the old unit comes right out and the new one fits perfectly - and thanks to MB desiging a pro socket, you dont need to worry about bolt alignment as they all self-locate making it much easier to work since the repair is done all by feel rather than by vision.
tested the new blower motor these last 2 weeks, in all AC and HEAT modes, AUTO and MANUAL, and everything works great. PLUS the new blower has an audible "power down" about 1-2 seconds after you shut the car off, meaning its very obvious that you HEAR a power down (and thankfully never a power UP meaning i no longer have to worry about something running all night when i dont want it to and waking up with a car that wont start.
just want to thank everyone in this wonderful thread for the great information and wisdom on the root cause of this weird electrical issue. i wanted to add my experience as well, in the event it can help some future w164 owners. this is also a great time to change out both cabin air filters as well!
huge shoutout as well to @srtdc for their knowledge and wisdom on the underlying cause!
The following 3 users liked this post by hilikusdrums:
#32
There is a constant 12 volts to the blower motor via the separate 2 wire connector. There are 2 connectors. A 2 wire heavy connector for the 12 v and a small multi wire (I think there is 8 wires) connector. The blower is switched on/off by the CAN bus connector to the PCB.
I think you are looking at this that it turns on/off the 12 volts...The 12 volts is always present. The blower is not shorting, there is no relay, the b,lower is inadvertently turned on by the PCB.
The PCB is not a "resistor". Its a data (CAN BUS) receiver that turns the blower on/off, controls the speed, etc.
I think you are looking at this that it turns on/off the 12 volts...The 12 volts is always present. The blower is not shorting, there is no relay, the b,lower is inadvertently turned on by the PCB.
The PCB is not a "resistor". Its a data (CAN BUS) receiver that turns the blower on/off, controls the speed, etc.
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Mark Pasieka (02-27-2023)
#33
Ok everyone problem solved. I just installed a new used oem blower motor and everything is ok. I did open the old one and the resistor was dry but did seem to have had dry residue from moister.
Everything is fine now. So if youre experiencing the same symptoms open up the blower motor and check out the resistor. Unlike the Audi/VW where the resistor is separate, in the GL its built in/ part of the motor.
If you need instructions on how to get to it I can take some pictures but its fairly easy to do.
Everything is fine now. So if youre experiencing the same symptoms open up the blower motor and check out the resistor. Unlike the Audi/VW where the resistor is separate, in the GL its built in/ part of the motor.
If you need instructions on how to get to it I can take some pictures but its fairly easy to do.
#34
Similar problem with 2011 R350
I have a similar issue with a 2011 R350 where when the engine is off and key removed a fan blows from the vents in the third row of seats only. This will continue until the car is started next. I followed instructions from this thread, removed the blower motor from the passenger footwell. The circuit board did not appear moldy in any way. I cleaned the 4 spade contacts but these showed no sign of corrosion.
the blower continued to blow from the third row seats while I had the blower motor removed suggesting that the problem lies elsewhere. Unsurprisingly, after refitting the problem remains as before.
any suggestions please?
the blower continued to blow from the third row seats while I had the blower motor removed suggesting that the problem lies elsewhere. Unsurprisingly, after refitting the problem remains as before.
any suggestions please?
#35
I haven’t seen anyone mention it, and I apologize if I am telling everyone something they already know.
If you run your air conditioner, before you shut the engine down, put environmental control to vent, and let it run for a couple of minutes.
It will cause more wear and tear on motor, compressor and accessory belt if you shutdown engine with air conditioning on, and or start the engine with it on.
The reason for switching to vent is for the reasons previously mentioned in the thread.
Running the vent helps to remove moisture and the problems moisture causes.
If you run your air conditioner, before you shut the engine down, put environmental control to vent, and let it run for a couple of minutes.
It will cause more wear and tear on motor, compressor and accessory belt if you shutdown engine with air conditioning on, and or start the engine with it on.
The reason for switching to vent is for the reasons previously mentioned in the thread.
Running the vent helps to remove moisture and the problems moisture causes.
#36
Super Member
Joined: Jul 2016
Posts: 529
Likes: 103
From: NE OHIO
1998 SL500,2011 GL550,2009 ML350,past 1995 E320 Cabrio ,2005 ML500,2006 ML500,1996 SL500,1972 280SEL
pictures
I have a similar issue with a 2011 R350 where when the engine is off and key removed a fan blows from the vents in the third row of seats only. This will continue until the car is started next. I followed instructions from this thread, removed the blower motor from the passenger footwell. The circuit board did not appear moldy in any way. I cleaned the 4 spade contacts but these showed no sign of corrosion.
the blower continued to blow from the third row seats while I had the blower motor removed suggesting that the problem lies elsewhere. Unsurprisingly, after refitting the problem remains as before.
any suggestions please?
the blower continued to blow from the third row seats while I had the blower motor removed suggesting that the problem lies elsewhere. Unsurprisingly, after refitting the problem remains as before.
any suggestions please?
It is possible the board is shorted thru the power FETS also. If you are good with a multi meter you can follow the power trace and see if it is shorted thru the turn on device.
Last edited by vesiadog; 04-01-2024 at 08:47 PM. Reason: wording
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Dinismb (04-02-2024)
#37
Thread Starter
Member
Joined: Oct 2016
Posts: 187
Likes: 22
2005 Mercedes C230 Kompressor, 2008 GL 320 CDI, 2008 ML320 CDI, 2016 GLE 300d AMG Night Package
I have a similar issue with a 2011 R350 where when the engine is off and key removed a fan blows from the vents in the third row of seats only. This will continue until the car is started next. I followed instructions from this thread, removed the blower motor from the passenger footwell. The circuit board did not appear moldy in any way. I cleaned the 4 spade contacts but these showed no sign of corrosion.
the blower continued to blow from the third row seats while I had the blower motor removed suggesting that the problem lies elsewhere. Unsurprisingly, after refitting the problem remains as before.
any suggestions please?
the blower continued to blow from the third row seats while I had the blower motor removed suggesting that the problem lies elsewhere. Unsurprisingly, after refitting the problem remains as before.
any suggestions please?
#38
The following users liked this post:
Dinismb (04-02-2024)
#39
Super Member
Joined: Jul 2016
Posts: 529
Likes: 103
From: NE OHIO
1998 SL500,2011 GL550,2009 ML350,past 1995 E320 Cabrio ,2005 ML500,2006 ML500,1996 SL500,1972 280SEL
Fan motor
*CONFIRMED FIX* on 2008 ML350! i had this issue happen to me in 2023, so wanted to add my story as well- as this can still happen to the w164 even in '23! here's a brief synopsis of what was happening on my w164- every once in a while the battery would randomly die overnight or after sitting for awhile, i just chalked that up to some odd anomaly that i would need to keep an eye on. however by february of 2023- i had noticed the HVAC blower motor would stay on after i turned the key off. while i did read one thread comment that said MB does this to avoid moisture build up in blower ducts, and of course theres the "REST" feature... this was clearly neither of those as the blower motor would just run constantly until the battery was dead.
thanks to this thread, i was able to diagnose and solve this very weird problem. i HATE electrical issues on cars, as they can be a nightmare to trace down.
as other users have pointed out, what ends up happening is that water from carwashes/rain/snow/etc will fall into the hood vent and drip down into the drain channel. most of it will drain as needed, but some water may get by (esp if the drain becomes plugged) and will seep into the blower motor where it will rust out the main center bearing and drip down through it and get into the bottom where the circuit board is, and short it all out- causing the fan to have a mind of its own.
i have attached a pic of my stock blower and the replacement from ebay, you can see the design revisions as well as the rusted out center bearing on the old fan on the left. especially of note, notice how the old blower on the left has HUGE openings that can easily allow water into the core of the motor. the new one is sealed up tight like an umbrella. i suspect this will be a much better design.
the new part was 100 bucks on ebay, and appears to be a revised version of the stock Siemens blower that came on the car. i suspect this revised blower motor may not have this annoying issue, but i will report back if anything comes up in the future.
the fix was not too bad, the hardest part was unplugging the old fan plugs (2 of them) in february with cold fingers on a garage floor. one plug has two clips on each side, the other one may require a small screwdriver to help you move the clip on the side. but once you get the old fan out (4 torx bolts) after dropping the panel below the glovebox (also 4 torx - same as the fan) the old unit comes right out and the new one fits perfectly - and thanks to MB desiging a pro socket, you dont need to worry about bolt alignment as they all self-locate making it much easier to work since the repair is done all by feel rather than by vision.
tested the new blower motor these last 2 weeks, in all AC and HEAT modes, AUTO and MANUAL, and everything works great. PLUS the new blower has an audible "power down" about 1-2 seconds after you shut the car off, meaning its very obvious that you HEAR a power down (and thankfully never a power UP meaning i no longer have to worry about something running all night when i dont want it to and waking up with a car that wont start.
just want to thank everyone in this wonderful thread for the great information and wisdom on the root cause of this weird electrical issue. i wanted to add my experience as well, in the event it can help some future w164 owners. this is also a great time to change out both cabin air filters as well!
huge shoutout as well to @srtdc for their knowledge and wisdom on the underlying cause!
thanks to this thread, i was able to diagnose and solve this very weird problem. i HATE electrical issues on cars, as they can be a nightmare to trace down.
as other users have pointed out, what ends up happening is that water from carwashes/rain/snow/etc will fall into the hood vent and drip down into the drain channel. most of it will drain as needed, but some water may get by (esp if the drain becomes plugged) and will seep into the blower motor where it will rust out the main center bearing and drip down through it and get into the bottom where the circuit board is, and short it all out- causing the fan to have a mind of its own.
i have attached a pic of my stock blower and the replacement from ebay, you can see the design revisions as well as the rusted out center bearing on the old fan on the left. especially of note, notice how the old blower on the left has HUGE openings that can easily allow water into the core of the motor. the new one is sealed up tight like an umbrella. i suspect this will be a much better design.
the new part was 100 bucks on ebay, and appears to be a revised version of the stock Siemens blower that came on the car. i suspect this revised blower motor may not have this annoying issue, but i will report back if anything comes up in the future.
the fix was not too bad, the hardest part was unplugging the old fan plugs (2 of them) in february with cold fingers on a garage floor. one plug has two clips on each side, the other one may require a small screwdriver to help you move the clip on the side. but once you get the old fan out (4 torx bolts) after dropping the panel below the glovebox (also 4 torx - same as the fan) the old unit comes right out and the new one fits perfectly - and thanks to MB desiging a pro socket, you dont need to worry about bolt alignment as they all self-locate making it much easier to work since the repair is done all by feel rather than by vision.
tested the new blower motor these last 2 weeks, in all AC and HEAT modes, AUTO and MANUAL, and everything works great. PLUS the new blower has an audible "power down" about 1-2 seconds after you shut the car off, meaning its very obvious that you HEAR a power down (and thankfully never a power UP meaning i no longer have to worry about something running all night when i dont want it to and waking up with a car that wont start.
just want to thank everyone in this wonderful thread for the great information and wisdom on the root cause of this weird electrical issue. i wanted to add my experience as well, in the event it can help some future w164 owners. this is also a great time to change out both cabin air filters as well!
huge shoutout as well to @srtdc for their knowledge and wisdom on the underlying cause!