Blower Motor Fuse ?Melted?
 

Hi Everyone,

Having a problem with my 1986 300E blower motor. The fuse is getting very hot and melting the plastic, but not blowing the fuse. The fan stops when the melted plastic makes the fuse no longer contact the fuseblock. I can't really think what would cause this except excessive current draw.. maybe a blower motor resistor or regulater? Anyone heard of this before in these cars? I have a mutimeter, where should I test for this and what should I inspect? I appreciate everyones input


Thanks,

Jason McNeese

IF you are talking about fuse # 12 in the fuse box, then you need to have an external fuse holder installed. THIS is a factory mod that should have been done back in 1987.

Thanks
 

Thank you very much 'Doc, should I stick with the same amperage fuse?

The parts for the factory mod included a 30A strip style fuse which can take upto 40A.
The parts for this mod are still avail.

What is the part number for this "strip" 30 Amp fuse setup (box, fuse, screws, etc...)? Does Mercedes Shop carry this?

Thanks.
Brent Edwards

Have the same exact problem with my 1986 560... the blower's working now and I haven't replaced the fuse with the external one because I've kept replacing the fuse (by using the copper filament of the blown fuse and sticking it down into the melted cavity to make a connection since the lower contact is pretty much gone) and so far its blowing. I'll go out in the parking garage and get the part # for the external fuse (that I haven't installed since its still blowing) and it does have a 30 amp strip fuse.

How difficult is it to install this? Can you just remove the top portion containing the contacts to expose the wires or will I end up cutting my wire insulation to access them? I ask because I unscrewed the actual box to lift it and the wires that were secured with the insulation prevented me from lifting it and it looked like I may have to cut it to get to the wire so I put it right back and stuck the external fuse in my trunk until I HAD to replace it and just haven't taken a look at it since. Any help is appreciated and thanks in advance

Alan;)

Part # for retrofit kit?
 

Hi

This board is great - I am really being helped a lot as I restore this 560 SEL.

Does someone have the Part # for the retrofit kit from Mercedes to install the external fuse for the Blower Motor? I called the 3 local Mercedes dealers, parts departments, and none could immediately help me. Each said that if I had a part number for the Retro Kit, they could track it down.

I am a little concerned with driving my car with a melting fuse box - and I live in Canada, so a heater motor is a necessary as fuel!

Thanks
Richard

The part number for the 30 amp upgrade is 126 540 30 13. I had to look back through records because I couldn't locate my earlier post with directions. Seems to have been archived and I can't figure out how to search the archived posts. There is a brief how-to among the current posts, try a search for "fuse box upgrade", but that post did not have the part number.

The_Professor ...

I am in the process of replacing my blower motor, it seems that over time these wear out, and begin to pull A LOT of current, thus these fuse / melting issues. I realize it's cold where you are, but I would disconnect this fuse until you have fixed this issue. Moving to the external box is a good idea, but even doing so you probably need to consider looking into replacing the blower motor.

--
Brent

Thanks a lot guys!
 

wow - fast turnaround - thanks!

Yes, I was wondering about why this particular fuse might be drawing lots of current at this point in time. Doesn't the same blower motor also push air around for the Air Conditioning too? Hence, shouldn;t someone in Florida have a similar problem?

There is a guy just south of me that has developed some repair manuals and he is selling a Heater motor "kit" with a pair of new brushes. Not being an electrician, I have no idea if this would solve the high-current-draw problem (i.e., would worn brushes draw more current?), and also reduce the amount of money I have to spend. I have heard that blower motors are quite expensive and he charges $30 for the "kit", including the "Blower Motors for Dummies" manual (something I would definitely need).

The URL for this kit is:

http://www.**************.com/store/item.php?item=107%20Heater%20Motor%20Repair%20Kit


Thanks again.

My blower fuse problem surfaced in California when the AC was blowing max hi. I imagine the same outcome when blowing max hi heat. It is an easy upgrade, takes maybe 20-30 minutes for an average DIYer, I knocked mine out in about 15 minutes working at night. As MBDoc stated you can bump the strip fuse to a 40 amp max if needed. Much easier than replacing the blower unless the blower is almost dead.

Hi all.

This is something I can help explain. It applies to almost anything electrical.

Current (amps) + resistance (bad connection) = heat (something burning or melting.)
This is not to say that the blower motor is not bad but does say that there is a bad connection in the fuse block. Fix the bad connection first, which in this case is to install the external fuse holder and fuse.
The sole purpose of the fuse is to protect the wiring in the system. If something shorts out then the fuse should blow to protect the wiring.
Please, please DON'T ever put in a higher amperage fuse then what is called for unless you want to burn the car up and possible total it. Believe me, I have seen many cases where a larger fuse was installed and the vehicle was either totaled or the bill was very high.