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Wiper Motor or Blower Motor / Resistor Pack Failure??

6K views 3 replies 2 participants last post by  jangr320 
#1 ·
Looks like our 98 ML320 just went into "old age" failure mode this weekend - the ventilation system just started blowing out a acrid electrical burning smell.

Fuse #44 blew, and the wipers stopped working along with the power mirror adjustment. The AC blower motor still worked fine!

I suspect either a bad resistor array for the AC system or perhaps even a bad wiper motor - there was a wisp of smoke coming from under the plastic cowl cover at the base of the windshield on the DS next to the WW jet.

I checked and replaced fuse #44 and all works as NORMAL again, except I get the strong odor of burned electrical components.

Anyone have any ideas? Anyone tackled changing the wiper motor or AC blower resistor array? I don't have a shop manual, so it's pretty exploratory - I have no problem working on cars (have 3 older Porsches to keep that skill in line) - electrical or mechanical. Let me know what's involved, your experiences.

YIKES!! Just checked a source and it quoted 15.5 hours for Re&Re of the heater case assembly!! Hope it is not the resistor array!

WW motor is a 2.4 hour replacement and looks like the motor costs $34.50!

Thanks to all in advance! These forums are a godsend! [:)]
 
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#2 ·
The cabin fan has a resistor bank located near the cabin filter. You can check if it is bad by switching through all the fan speeds. If one or more are out, there is your culprit. It only takes a few minutes to remove the resistor. It is a special order item and I cannot recall the cost.

As for AC fan resistors, I am not sure there are any.
 
#3 ·
mickey.1430 - 11/12/2004 10:43 PM

The cabin fan has a resistor bank located near the cabin filter. You can check if it is bad by switching through all the fan speeds. If one or more are out, there is your culprit. It only takes a few minutes to remove the resistor. It is a special order item and I cannot recall the cost.

As for AC fan resistors, I am not sure there are any.
Hey thanks Tom! Just what I needed to know - so I am guessing that you mean the Passenger Side air filter under the glovebox area. I suspect it is either that blower resistor array or the wiper motor that another lister had a similar problem with in his E Class sedan. Similar symptons and the acrid burned electrical component smell.
 
#4 ·
Fuse #44 wiring harness for Blower Motor WARRANTY??

Just spent 1 hour to get the blower out (it checks out fine), the Blower Resistor Array (perfect condition, no overheating on the ceramic case) and cleaned out the cabin filter. Thanks to all the listers for posts and photos - so easy to get to these items in the PS footwell below the glove box!

I was worried that they were all buried deep in the bowels of the heating AC case, but luckily, MB designed it for easy maintenance.

So it looks like the blower fan / resistor array is fine and the wipers are working.

Could it be the Fuse #44 wiring harness? I came a cross several posts on the forums noting the famous (infamous?) Fuse #44 and what it serves.

Quote" Check the fan fuse F44, 30A, green. (from Grant in Tampa) The updated harness is 163-540-00-35, AC wiring is PK163-AC, 40 amp fuse is 910153-000000. (from Stuart Sloane)"

Anyone had a successful WARRANTY claim on this in Canada??
 
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