Heater Blower problem

[touchwoodsden]

I am sorry, but I only seem to visit when my car has a problem. At least if I post my problem it may help anyone else who has the same prob.

My 1999 C220 CDI heater blower switch works when it feel like. It either works properly as it should or not at all. I can be driving along with it switched on (and not working), and then suddenly it will start. Once it starts, it will continue to run. At first it happend very occasionally but now it is virtually every day. I checked fusesand obvious stuff and all seem OK.

Does anyone have any similar experience? If it is the switch, HTF do you get to it?

Thanks for replies everyone.

James Mather
UK

[manny]

Had the exact same problem about 2 months ago.
Get a new blower ( worth about 100 pounds ).
Takes 15 minutes to change it. ;)

[Rocket]

I used a very light amount of motor oil in my blower to fix it on my 1995 C36...

[manny]

Originally posted by Rocket
I used a very light amount of motor oil in my blower to fix it on my 1995 C36... I had mine in & out so many times ( oiled it, cleaned it, etc ), I was afraid to wear out the screws that hold the blower in place. ;)

[Rocky]

how exactly do you take it out?

[manny]

Originally posted by Rocky
how exactly do you take it out? There are 4 or 5 torxhead screws ( either # 15 or 20 torx ).
Just undo them & the whole blower assembly will drop down. ;)

[Rocky]

Originally posted by manny
There are 4 or 5 torxhead screws ( either # 15 or 20 torx ).
Just undo them & the whole blower assembly will drop down. ;)

from where though? where the pollen filter is?

[Rocket]

Originally posted by Rocky
from where though? where the pollen filter is?

It's the black box held by four clips to the right of the pollen filter.

[touchwoodsden]

Er, thanks for replies guys. Useful stuff. Err, where is the pollen filter then?

James

[manny]

Originally posted by touchwoodsden
Er, thanks for replies guys. Useful stuff. Err, where is the pollen filter then?

James

Pollen filter is by your left foot ( passenger side ), blower motor by your right foot.
Both covers have little slide-away clips. ;)

[manny]

Originally posted by Rocky
from where though? where the pollen filter is?

To the right of the filter.
Open the access door ( looks the same as the filter door ).
You will also see an electrical connector going to the blower. ;)

[SLAMMED_C]

My 1999 C220 CDI heater blower switch works when it feel like. It either works properly as it should or not at all. I can be driving along with it switched on (and not working), and then suddenly it will start. Once it starts, it will continue to run. At first it happend very occasionally but now it is virtually every day. I checked fusesand obvious stuff and all seem OK.
It could be the blower motor as was mentioned before.. but it may also be the blower motor regulator.. and lastly it can be the head unit itself.. Myself Id guess its the regulator, Ive seen lots of them where they dont come on when you turn them on, or turn on when you want but the speed fluctuates by itself. The regulator is located in the same spot as the blower motor, actually bolted to the motor, and power actually goes into the regulator first then it goes to the blower motor.. the regulator "regulates" the speed of the blower motor, so my guess is a faulty blower motor regulator.

[Rocky]

Originally posted by SLAMMED_C
It could be the blower motor as was mentioned before.. but it may also be the blower motor regulator.. and lastly it can be the head unit itself.. Myself Id guess its the regulator, Ive seen lots of them where they dont come on when you turn them on, or turn on when you want but the speed fluctuates by itself. The regulator is located in the same spot as the blower motor, actually bolted to the motor, and power actually goes into the regulator first then it goes to the blower motor.. the regulator "regulates" the speed of the blower motor, so my guess is a faulty blower motor regulator.

Got a price slammed?

[touchwoodsden]

Well, tonight I took it out (the heater motor that is).
I put the procedure here for anyone with the same problem who hasnt done it before. I hope it helps. It really is very simple
On my RH drive it is under the LH dash "under-panel" which has lots of small holes in it. The under-panel is held on with 3 posidrive screws and it slides off backwards after removing the small footwell vent held on with one 1/2 turn plastic posi screw. (easily damaged). With panel removed, then you can see the blower housing and the pollen filter housing. The PF housing is the smaller of the 2. Both held on with sliding clips. Begs the question as to why Merc put easy access sliding clips on the blower motor housing (the PF housing I can understand). Do they expect problems? I have never had this on any other car I have owned!!
Anyway..remove electrical connector (obvious) and then slide clips and remove cover. U can then see the motor and regulator. Remove regulator first (2 torx screws) cos there is a torx screw hidden under it, one of 4 retaining the motor. The reg has plug in connector to motor and has porcupine cooler on its back (visible after removing).
I made a note of all serial and model numbers I could find to aid a "google search" for spares if needed.
So remove reg, then remove motor. It doesnt appear possible to remove impeller from motor shaft. The motor turned freely but not frictionless. I put drop of oil on the bush u can see but the other is not accessible.
The brushes looked worn (NB worn, not worn out) but I think I will see if replacements are available. The comm is fine. I put 12volts on the motor (not the reg) and this produced a healthy torque start spin. I guess the problem isnt the motor.
It now comes down to regulator and/or switch.
I am inclined to go with Slammed's diagnosis of regulator.(modern car electronics seem to be very unreliable...why not use a good old fashioned rheostat I ask.)
Anyway, I put it all back and it works fine( for now), so we shall see.
I shall post here with news.
Regards to everyone and thanks for all replies.
James
North Wales UK

[touchwoodsden]

BTW, mine sometimes doesnt come on but when it does, it stays on (unless I switch it off) and it is always at the speed it should be (if it does actually come on). The speed doesnt fluctuate
James

[SLAMMED_C]

I think the regualtor is somewhere in the neibourhood of $250-300. (canadian that is)

[Rocky]

OUCH :(

[1998K]

Up to this tread, I copy and post some info someone probably already saw but may be usefull for the other.

http://mbclub.co.uk/forums/showthread.php?t=3593

Please I hear a small rattling noise at a specific speed (about n.4) that disappear above but also below, I belive it came from the fan. The nice thing is the same rattle I can hear fromt that area passing over potholes:I'm wondering if fan bearing shaft may be worn to cause that the fan blade touch someting (protection!?).

I've read on MBWord.org that someone pusches the shaft to avoid possible parts contacts.

Does someone have some experience?:(

[touchwoodsden]

I had a sort of "Zizzlle" noise, not very loud, rather like a dasboard rattle, which i thought was coming from the fan or from a leaf from a tree trapped in the air duct. It only happened at certain speeds. I tried in vain to locate it . When I moved my head it seemd to move away. I even bought an engineers stethoscope off Ebay (great tool) to try and locate it.
It turned out to be the sunvisor vibrating on the head lining!!!!!!!!

I hope this may help.

Regards

James
N Wales

[1998K]

Originally posted by touchwoodsden
I had a sort of "Zizzlle" noise, not very loud, rather like a dasboard rattle, which i thought was coming from the fan or from a leaf from a tree trapped in the air duct. It only happened at certain speeds. I tried in vain to locate it . When I moved my head it seemd to move away. I even bought an engineers stethoscope off Ebay (great tool) to try and locate it.
It turned out to be the sunvisor vibrating on the head lining!!!!!!!!

I hope this may help.

Regards

James
N Wales

Thanks for this info, in my case I'm quite sure it's related to the fan or something in the air duct. But I'm more convinced to the fan.

Please does someone have some experience with the fan shaft modification to avoid contacts of fan blades?

[touchwoodsden]

The fan assembly can be removed in 5 minutes. It will be esay to see if the blade is touching anything. Remember that the faster the blower speed, the faster the noise.
regards

[Shude]

Originally posted by 1998K
Up to this tread, I copy and post some info someone probably already saw but may be usefull for the other.

http://mbclub.co.uk/forums/showthread.php?t=3593
Nice to see my HOWTO getting around :D

My fan is kinda working atm but it will need replacing soon due to the brushes being worn out :(

[1998K]

Originally posted by touchwoodsden
The fan assembly can be removed in 5 minutes. It will be esay to see if the blade is touching anything. Remember that the faster the blower speed, the faster the noise.
regards

Yes as per Shude HOWTO it seems very easy. In my case the rattling noise come at ab.3 speed but it's noticable passing over potholes!:(

yes really strange but this is the main reason I'd like to verify the fan blade...fan speed 3 is really never utilized by me so this is not a problem.

;)

as soon I'll check.

[1998K]

Originally posted by Shude
Nice to see my HOWTO getting around :D

My fan is kinda working atm but it will need replacing soon due to the brushes being worn out :(

Thanks for this Shude. Please keep us informed on the brushes if you'll find some replacement or you need new fan.

:)

[Rocky]

I put off posting this but i guess i'll give it a try.

On coldest setting, my blower set on high, it's super fast.

On hottest or warm settings, when I turn the blower up all the way, it's like blowing half the power.

Any ideas?

[touchwoodsden]

Originally posted by 1998K
Thanks for this Shude. Please keep us informed on the brushes if you'll find some replacement or you need new fan.

:)
Does anyone know if spare brushes are available.? Mine are worn to.
Thanks

[1998K]

Originally posted by Rocky
I put off posting this but i guess i'll give it a try.

On coldest setting, my blower set on high, it's super fast.

On hottest or warm settings, when I turn the blower up all the way, it's like blowing half the power.

Any ideas?

strange, sorry I have no idea:(

[1998K]

Originally posted by touchwoodsden
Does anyone know if spare brushes are available.? Mine are worn to.
Thanks

It seems (Shude will confirm) that are not available as a spare part. I know he's looking to some local electric alternator repair shop. I belive is all a matter of luck to find locally.

As far as your noise problem is it solved (since related to the sunvisor) or is it related the the worn brushes? I don't know if this is really possible.

Still waiting some time to dismount the blower to check interference of the blades, but does someone have really heard of this possibility?:rolleyes:

[1998K]

To up-date you guys: I've dismounted to check and cleaned the blower motor and relevant components. As I can saw all was OK (also the bushings are OK) there are not any sign of fan interference or contacts in way of sourronding plastic protection.

After the re-assembly the vibration is gone, hoping it will last.

;)

[SLAMMED_C]

I put off posting this but i guess i'll give it a try.
On coldest setting, my blower set on high, it's super fast.
On hottest or warm settings, when I turn the blower up all the way, it's like blowing half the power.
Any ideas?
Id have to check my car.. but Im pretty sure its normal.
maybe faster blower speed on cold for the A/C so it blows fast enough to get cold air quickly, and a bit slower on the heater setting so it doesnt cool down the hot air before it gets to you.