1995 E320 wagon

super quick question. on my 95 wagon the blower strip fuse finally cracked, would there be any problem with replacing it with a blade-fuse holder and say a 30A fuse? Having HVAC is pretty important, and I'd hate for it to fail on me the next time while I am on the road or something. Using the more commonplace blade fuses would be a lifesaver no?

On reply (From the Expert)

So, Why didn't they use the ATC (blade) type fuse in that application?

Thank You.

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'84 300SD sold
124.128

That blower fuse design started in 1986 & MB rejected using ATC type fuses due the the many failures of fuses & fuse boxes (BMW & VW) that used that design.
MB first used ATC style fuse on the W140 chassis(late 1991) & all replacement chassis types.

Rarely does MB make that type of change during a production run.

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MERCEDES Benz Master Guild Technician (6 TIMES)
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Mercedes Benz Star Technician (2 times)
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27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

MB DOC,

So, it would be O.K. to retrofit the separate blower fuse(shock tower location)
with an ATM type fuse and holder?

The strip type are subject to the "Crack" or Melt syndrome.

'Has the industry solved the Q.C. problems with the ATC type?

Thank You

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'84 300SD sold
124.128

Yes, a high quality ATC fuse holder will work just fine.
Make sure that the amperage raring of the wiring is high enough.

Yes, ATC style fuses will work just fine if the design is correct.
MB has had some issues with ability to design for correct current flow.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

I don't quite get the MB design problem with current flow?

(Do Germanic electrons have a counter-flow operation option?)

It's my understanding that electrons only flow in one direction
[Negative to Positive]
(At least on this side of the Atlantic)

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'84 300SD sold
124.128

Not which way it flows, but with how heavy the wiring must be to carry the current flow.

ON about 60% of blower motor circuits they seem to under-rate the amount of consumption of the motor! Going back to the late 70"s

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Motors with a draw of 30A and up use strip fuses b/c motors have a start-up draw that excedes the fuse rating and a strip fuse will also take the start-up demands with a time delay. That is why they are open fuses. [ heat dissipation]. Quite commonly used on industrial equipment.
..the problem with them is they heat fatique and crack from the constant expansion/contraction of variable current flow of the motor circuit.
A trick when using these is to put a slight curve/bend in the link when installing them so that the link has an expansion factor to work with. If it is straight and tight at install, it has no flex parameters for expansion/contraction. A sligh curve allows the fuse to flex in length between the 2 terminal binding post, thereby eliminating the crack failures one sees on them.
But . they still fatique from use and aged links should be changed before they blow ...Normal maintainance.

__________________
A Dalton

A.D. ,

If the strip type fuse has a "Stress Relief" bend it'll last longer(and not be as
prone to cracking) [an advantage the newer blade type fuses cannot match]

M.B.DOC,

The wiring diagram shows the Aux Fuse holder (for the Blower motor) has
4mm wires.
The ground circuit has 2.5 mm wires.
The wires from the Electronic Blower Control Unit that feed both sides of the
Blower Motor are not marked as to wire diameter(should they not be at least
the same 4mm diameter as the fuse holder?)
Hypothetically,Rewiring the whole Blower power circuit (everything mentioned
above)with 6mm diameter wire would correct for any "Lack of Current Carrying Equation Capabilities"
[or as you put it,"under-rate the amount of consumption of the motor"]???

__________________
'84 300SD sold
124.128

That is correct ...the strip fuse is a better fuse for that circuit...which is why they eliminated the earlier versions to the modified aux fuse holder w/strip.

But , the main failure on all of these is the wiring was smaller than needed and the anticipated draw higher b/c they did not allow for bearing and brush wear [ additional draw] of the blower motor as they aged.
Same deal on the Aux fans ...they finally recommended upping the low fan fuse from 15 to 25 b/c of constant low fan fuse failure w/ac ON.

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A Dalton

having plenty of experience with those fuse holders and relays etc. from my E-code headlamp and 80/100 bulb project, I had plenty of spares. I used an ATC fuse holder very similar to this since its leads are 12g braided copper.



a couple of ring terminals and a 30A fuse (do to think thats high enough?). blower works like a champ so far. I can post picts if you really want. its pretty straight forward.

Like Doc says..get the best fuse holder you can get your hands on...this circuit is high amp and the actual wire size and connections are as important as the fuse............

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A Dalton