Blower fuse question and part number help needed.

[tobyd]

Hi,

I need a little bit of help. My heater blower stopped working today on my '94 E280 and I looked straight away at the fuses and it had gone - easy fix I thought. On closer inspection the bottom end of the fuse had melted at some point so I had to get it out with small pliers.
I could then see that the metal cup it sits in had also got hot an it had 'sunk' and got covered in the black plastic of the surround it sits in - thus the new fuse couldn't make contact.
As a temp fix I have managed to drill of the melted plastic so there is a contact for the lower end of the fuse to meet.

Now the help bit: Can someone suggest a reason why this would have got so hot?

Can someone help with a part number for the black plastic fuse tray that the fuses sit in and the wires screw to underneath (this is seperate from the box).

Thanks in anticipation.
Toby

 

[anyweb]

it's most likely getting hot because of a problem with the blower motor itself, if the blower motor cannot turn for some reason (blockage, worn brushes/age) then the power may backfire back to the fuse causing it to warm up to such a degree that it melts the plastic around it,

i'd suspect that the fuse in your fuse holder was too high a amp rating, check your manual for what the fuse should be, and if possible compare that to what fuse you removed

i'm no electrician so these are just my guess's however I have successfully removed a heater blower motor (brushes fell off causing catastrophic failure of the fan) from an old 190d, and replaced it with a new one, so I'm familiar with that part of the problem,

the motors do go, for one reason or another, and when they do you should replace or repair them as soon as possible, because winter is coming soon and you cannot drive with your inside front windscreen covered in frost (in this country at least)

good luck !

cheers
anyweb

 

[television]

Could you think about adding a separate fuse holder for this, it could be much easier than replacing the whole block, are there any blanks in it not used, if there are you would only have to move one wire or bridge it.

Once the contact is made good, the heating should stop, it cant be a current fault as the fuse would have blown

 

[kth286]

E-class cars of that age are notorious for bad fuses which make only intermittent contact. People in the know will change all fuses periodically on that car.

So, to answer your question, it is arcing between the fuse and it's holder that causes the plastic to melt, particularly on a high power circuit like the blower motor.