Re: [MBZ] 1985 300TD Blower Motor

[Karl Wittnebel via Mercedes]

Someone posted about this in the archives a year or two ago.

My money is on the rotor. The brushes wear the contacting metal off in a
thin groove around the rotor. This can be diagnosed by pushing upward on
the bare metal end of the rotor from below, which changes the point of
contact with the brushes and restores motor function, until you let go. It
requires a new motor.

On Feb 10, 2017 6:39 AM, "Dan--- via Mercedes" 
wrote:

Buddy with a 300TD is asking:

> The blower motor has been intermittent on this car since I purchased it
three years ago.  If the blower did not come on you could wrap the dash and
it would roar to life.  About a month ago the blower stopped working
altogether.  I took it apart and installed new brushes and the others were
very worn.  However after reinstalling last night blower still does not
function.
>
> Even if the blower did not fire up, prior or now,  the AC push button
control is still sending a signal to the compressor as you can feel/hear
the compressor engage just no blower.  The tapping of the dash to make
blower fire up is what's throwing to me.  I guess it COULD be the push
button control.  Maybe it's a short elsewhere.  To be clear no matter if
you tap the dash now or not the blower will not turn on under any
circumstance.

Suggestions? I doubt the PB unit is at fault, but to be honest, I've never
had to deal with blower issues in a Type III ACC system beyond brush
replacement.

Thanks,

-D


Sent from my iPad

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Re: [MBZ] 1985 300TD Blower Motor

[David Bruckmann via Mercedes]

As Kaleb said, ignition switch is an easy thing to check. Also note that the 
aux coolant pump (which eventually fails) is "fused" only via the pushbutton 
unit. If that coolant pump has seized, it can take the pushbutton unit with 
it...


>> On Feb 10, 2017, at 8:38 AM, Dan--- via Mercedes  
>> wrote:
>> 
>> Buddy with a 300TD is asking:
>> 
>>> The blower motor has been intermittent on this car since I purchased it 
>>> three years ago.  If the blower did not come on you could wrap the dash and 
>>> it would roar to life.  About a month ago the blower stopped working 
>>> altogether.  I took it apart and installed new brushes and the others were 
>>> very worn.  However after reinstalling last night blower still does not 
>>> function.
>>> 
>>> Even if the blower did not fire up, prior or now,  the AC push button 
>>> control is still sending a signal to the compressor as you can feel/hear 
>>> the compressor engage just no blower.  The tapping of the dash to make 
>>> blower fire up is what's throwing to me.  I guess it COULD be the push 
>>> button control.  Maybe it's a short elsewhere.  To be clear no matter if 
>>> you tap the dash now or not the blower will not turn on under any 
>>> circumstance.
>> 
>> Suggestions? I doubt the PB unit is at fault, but to be honest, I've never 
>> had to deal with blower issues in a Type III ACC system beyond brush 
>> replacement.
>> 
>> Thanks,
>> 
>> -D


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Re: [MBZ] 1985 300TD Blower Motor

[clay via Mercedes]

I just picked up one in the goodie boxes that accompany the free to me SD.  So 
far all the bits have been in great working condition and I think the PO tested 
everything prior to putting it on the parts shelf

clay


> On Feb 10, 2017, at 7:02 AM, Jim Cathey via Mercedes  
> wrote:
> 
> Solder joints inside the PB array, _especially_ the two side boards that
> run the temperature dial and the blower speed overrides, are prone to
> cracking and failing.  The fix is simple.  That system, with the narrow
> translucent "Auto" speed button, also uses a separate blower speed
> controller relay, which could be failing.  Again, solder joints is my first
> suspect in this vintage, followed by electrolytic capacitor failure.  Both
> are straightforward fixes, for he who can solder.
> 
> -- Jim
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> 
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> 
> To Unsubscribe or change delivery options go to:
> http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
> 


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Re: [MBZ] 1985 300TD Blower Motor

[Curt Raymond via Mercedes]

Might explain why pounding the dash fixed the problem before...
-Curt

  From: Fred Moir via Mercedes <mercedes@okiebenz.com>
 To: Mercedes Discussion List <mercedes@okiebenz.com> 
Cc: Fred Moir <fredh.s...@hotmail.com>
 Sent: Friday, February 10, 2017 1:23 PM
 Subject: Re: [MBZ] 1985 300TD Blower Motor
   
Dan.

My experience with a non-functioning blower in my '85 TD was that the button 
for the 0 shut down did not quite return to the rest position.

Exercising the PB switches seem to have cleaned up whatever was sticking.

As ever, YMMV.

Otherwise, Jim is the expert.

Fred


Fred Moir.
Lynn MA.
Diesel preferred.



From: Mercedes <mercedes-boun...@okiebenz.com> on behalf of Jim Cathey via 
Mercedes <mercedes@okiebenz.com>
Sent: 10 February 2017 10:02
To: Mercedes Discussion List
Cc: Jim Cathey
Subject: Re: [MBZ] 1985 300TD Blower Motor

Solder joints inside the PB array, _especially_ the two side boards that
run the temperature dial and the blower speed overrides, are prone to
cracking and failing.  The fix is simple.  That system, with the narrow
translucent "Auto" speed button, also uses a separate blower speed
controller relay, which could be failing.  Again, solder joints is my first
suspect in this vintage, followed by electrolytic capacitor failure.  Both
are straightforward fixes, for he who can solder.

-- Jim
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Re: [MBZ] 1985 300TD Blower Motor

[Fred Moir via Mercedes]

Dan.

My experience with a non-functioning blower in my '85 TD was that the button 
for the 0 shut down did not quite return to the rest position.

Exercising the PB switches seem to have cleaned up whatever was sticking.

As ever, YMMV.

Otherwise, Jim is the expert.

Fred


Fred Moir.
Lynn MA.
Diesel preferred.



From: Mercedes <mercedes-boun...@okiebenz.com> on behalf of Jim Cathey via 
Mercedes <mercedes@okiebenz.com>
Sent: 10 February 2017 10:02
To: Mercedes Discussion List
Cc: Jim Cathey
Subject: Re: [MBZ] 1985 300TD Blower Motor

Solder joints inside the PB array, _especially_ the two side boards that
run the temperature dial and the blower speed overrides, are prone to
cracking and failing.  The fix is simple.  That system, with the narrow
translucent "Auto" speed button, also uses a separate blower speed
controller relay, which could be failing.  Again, solder joints is my first
suspect in this vintage, followed by electrolytic capacitor failure.  Both
are straightforward fixes, for he who can solder.

-- Jim
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Re: [MBZ] 1985 300TD Blower Motor

[Max Dillon via Mercedes]

My suggestion would be remove the motor and double check his work on the 
brushes, check the fuse.
-- 
Max Dillon
Charleston SC
'87 300TD
'95 E300
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Re: [MBZ] 1985 300TD Blower Motor

[Jim Cathey via Mercedes]

>
> Does the electrical section of the ignition switch feed the blower?
> ...didn't know what the rationale was for it.


Most of the accessories are fed from that switch.  That's normal, in cars.

-- Jim
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Re: [MBZ] 1985 300TD Blower Motor

[Kaleb C. Striplin via Mercedes]

The ignition switch feeds the blower. Sometimes the contacts get a little flaky

Sent from my iPhone

> On Feb 10, 2017, at 9:49 AM, Dan--- via Mercedes  
> wrote:
> 
> Why? Does the electrical section of the ignition switch feed the blower?
> 
> I recall hearing about this before, but didn't know what the rationale was 
> for it.
> 
> -D
> 
> Sent from my iPad
> 
>> On Feb 10, 2017, at 10:19 AM, Kaleb C. Striplin via Mercedes 
>>  wrote:
>> 
>> Yes that is true also. Start with the ignition switch first as it's easy to 
>> check.
>> 
>> Sent from my iPhone
>> 
>>> On Feb 10, 2017, at 9:02 AM, Jim Cathey via Mercedes 
>>>  wrote:
>>> 
>>> Solder joints inside the PB array, _especially_ the two side boards that
>>> run the temperature dial and the blower speed overrides, are prone to
>>> cracking and failing.  The fix is simple.  That system, with the narrow
>>> translucent "Auto" speed button, also uses a separate blower speed
>>> controller relay, which could be failing.  Again, solder joints is my first
>>> suspect in this vintage, followed by electrolytic capacitor failure.  Both
>>> are straightforward fixes, for he who can solder.
>>> 
>>> -- Jim
>>> ___
>>> http://www.okiebenz.com
>>> 
>>> To search list archives http://www.okiebenz.com/archive/
>>> 
>>> To Unsubscribe or change delivery options go to:
>>> http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
>>> 
>> 
>> 
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>> http://www.okiebenz.com
>> 
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>> 
>> To Unsubscribe or change delivery options go to:
>> http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
>> 
>> 
> 
> 
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Re: [MBZ] 1985 300TD Blower Motor

[Dan--- via Mercedes]

Why? Does the electrical section of the ignition switch feed the blower?

I recall hearing about this before, but didn't know what the rationale was for 
it.

-D

Sent from my iPad

> On Feb 10, 2017, at 10:19 AM, Kaleb C. Striplin via Mercedes 
>  wrote:
> 
> Yes that is true also. Start with the ignition switch first as it's easy to 
> check.
> 
> Sent from my iPhone
> 
>> On Feb 10, 2017, at 9:02 AM, Jim Cathey via Mercedes  
>> wrote:
>> 
>> Solder joints inside the PB array, _especially_ the two side boards that
>> run the temperature dial and the blower speed overrides, are prone to
>> cracking and failing.  The fix is simple.  That system, with the narrow
>> translucent "Auto" speed button, also uses a separate blower speed
>> controller relay, which could be failing.  Again, solder joints is my first
>> suspect in this vintage, followed by electrolytic capacitor failure.  Both
>> are straightforward fixes, for he who can solder.
>> 
>> -- Jim
>> ___
>> http://www.okiebenz.com
>> 
>> To search list archives http://www.okiebenz.com/archive/
>> 
>> To Unsubscribe or change delivery options go to:
>> http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
>> 
> 
> 
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> 
> To Unsubscribe or change delivery options go to:
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> 
> 


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Re: [MBZ] 1985 300TD Blower Motor

[Kaleb C. Striplin via Mercedes]

Yes that is true also. Start with the ignition switch first as it's easy to 
check.

Sent from my iPhone

> On Feb 10, 2017, at 9:02 AM, Jim Cathey via Mercedes  
> wrote:
> 
> Solder joints inside the PB array, _especially_ the two side boards that
> run the temperature dial and the blower speed overrides, are prone to
> cracking and failing.  The fix is simple.  That system, with the narrow
> translucent "Auto" speed button, also uses a separate blower speed
> controller relay, which could be failing.  Again, solder joints is my first
> suspect in this vintage, followed by electrolytic capacitor failure.  Both
> are straightforward fixes, for he who can solder.
> 
> -- Jim
> ___
> http://www.okiebenz.com
> 
> To search list archives http://www.okiebenz.com/archive/
> 
> To Unsubscribe or change delivery options go to:
> http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
> 


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Re: [MBZ] 1985 300TD Blower Motor

[Kaleb C. Striplin via Mercedes]

It is the ignition switch. Next time it does it jiggle the switch a little bit 
back and forth from the run position back toward off, just a small fraction of 
an inch, just a hair amount.

Sent from my iPhone

> On Feb 10, 2017, at 8:38 AM, Dan--- via Mercedes  
> wrote:
> 
> Buddy with a 300TD is asking:
> 
>> The blower motor has been intermittent on this car since I purchased it 
>> three years ago.  If the blower did not come on you could wrap the dash and 
>> it would roar to life.  About a month ago the blower stopped working 
>> altogether.  I took it apart and installed new brushes and the others were 
>> very worn.  However after reinstalling last night blower still does not 
>> function.
>> 
>> Even if the blower did not fire up, prior or now,  the AC push button 
>> control is still sending a signal to the compressor as you can feel/hear the 
>> compressor engage just no blower.  The tapping of the dash to make blower 
>> fire up is what's throwing to me.  I guess it COULD be the push button 
>> control.  Maybe it's a short elsewhere.  To be clear no matter if you tap 
>> the dash now or not the blower will not turn on under any circumstance.
> 
> Suggestions? I doubt the PB unit is at fault, but to be honest, I've never 
> had to deal with blower issues in a Type III ACC system beyond brush 
> replacement.
> 
> Thanks,
> 
> -D
> 
> 
> Sent from my iPad
> 
> ___
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> 
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> 
> To Unsubscribe or change delivery options go to:
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> 


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Re: [MBZ] 1985 300TD Blower Motor

[Dan--- via Mercedes]

Thanks, Jim.

I forgot about the side board solder joints, as the last PB unit I worked on 
was in my 350SDL which has a later design that eliminates this point of failure.

-D

Sent from my iPad

> On Feb 10, 2017, at 10:02 AM, Jim Cathey  wrote:
> 
> Solder joints inside the PB array, _especially_ the two side boards that run 
> the temperature dial and the blower speed overrides, are prone to cracking 
> and failing.  The fix is simple.  That system, with the narrow translucent 
> "Auto" speed button, also uses a separate blower speed controller relay, 
> which could be failing.  Again, solder joints is my first suspect in this 
> vintage, followed by electrolytic capacitor failure.  Both are 
> straightforward fixes, for he who can solder.
> 
> -- Jim
> 


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Re: [MBZ] 1985 300TD Blower Motor

[Jim Cathey via Mercedes]

Solder joints inside the PB array, _especially_ the two side boards that
run the temperature dial and the blower speed overrides, are prone to
cracking and failing.  The fix is simple.  That system, with the narrow
translucent "Auto" speed button, also uses a separate blower speed
controller relay, which could be failing.  Again, solder joints is my first
suspect in this vintage, followed by electrolytic capacitor failure.  Both
are straightforward fixes, for he who can solder.

-- Jim
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