30 Amp Blower fuse blown

[kouks]

So I've replaced the fuse and all works fine now, but the burn spot on the fuse was quite sooted and part of the fuse was melted, so plenty of energy and heat.

Does this mean the blower motor is about to toast itself and burn the car with it? I've read a few horror stories on the forum and don't want to be one of them. Any insight appreciated.

[Sir Montalbon]

It's probably a good idea to look at overhauling the electrical components. I recommend a new blower resistor, blower, and filter while you're in there. That will ease the electrical load on the circuit. Also, make sure you get any debris out while you're doing it all.

But first thing, change the fuse to 20A.

[moroza]

Electrical motors such as the fan blower tend to wear out such that they turn slower and draw more power. The brushes in mine were on their last legs when I replaced it two years ago. VDO brand is now made in China. I used OEM Behr (Germany, IIRC).

Carry a fire extinguisher in all cars.

[funfunfer]

So I've replaced the fuse and all works fine now, but the burn spot on the fuse was quite sooted and part of the fuse was melted, so plenty of energy and heat.

Does this mean the blower motor is about to toast itself and burn the car with it? I've read a few horror stories on the forum and don't want to be one of them. Any insight appreciated.

I had the same thing happen maybe last year. I watched a couple of flaming E34 YouTube videos and promptly replaced the blower motor. Replacement is in thru the engine compartment and wasn't too bad even with an S38 in the way.

[locknload]

Also helps to not run the fan any higher than "2" (if you can stand it) until you get the current draw figured out.

[katit2]

What mileage cars start to have this problem?

[kouks]

Thanks gents,

I like the idea of replacing the 30A fuse with a 20A instead. Bentley says the max draw should be 12A, so obviously something went way wrong to cook a 30A fuse that well.

[kouks]

What mileage cars start to have this problem?

I don't know if its mileage, it may be more old age. Mine is at 242k miles, so I'm guessing anything near or over the 200k mark is a candidate. My fan makes a faint squeeling noise at the lower fan settings, goes away at the 4 setting, so a bearing must be gone or going.

[katit2]

Ok, mine is at 99k, I will change fuse and. Lean/ replace filter

[zubbie]

What mileage cars start to have this problem?

My blower motor went at 120,000 km (80,000 miles). It's not the mileage of the car that wears out the bearings in the motor (which causes the high resistance / high current problem), but rather the fan hours of use in hot / cold conditions. My car came from Japan so I'm sure the a/c was on continuously.

[moroza]

(which causes the low resistance / high current problem)

Fixed.

[zubbie]

Fixed.

I see what you did there.... V=IR.....

I should have said mechanical resistance

[ross1]

Another thing for the OP to do is to clean up the burnt contacts for the fuse, just additional resistance/heat there when they are bad. There are some unused positions in the fuse box the wires could be moved to if the plastic has melted.

[atl530i]

Replace the final stage resistor, blower motor, cabin filter, and swap the fuse with a 20a fuse. Clean the cabin filter area out completely.

It's not exactly fun to replace it all.

[kouks]

^ Yea, that's the horror story I was thinking about. Replaced fuse with 20 amp and getting parts. I've done this on my e38, on that one the entire dash has to come out, this seems easier from all the DIYs of read (with an M50 engine).

[kouks]

Got er done! Posted this on the "What did you do today to your e34" forum, but wanted to close this tread correctly. I was blowing it off since I didn't want to do the work, but yesterday my daughter told me the car smelled like something was burning when she turned on the fan.

[E38740iMD]

glad the car was saved!!!!!!!!!!

- - - Updated - - -

i would have spitted out food if my daughter told me that out the blue

[moroza]

Huh. Neither the old nor the new cabin filter look to have a black plastic frame. Do they fit ok? I recently ordered a filter (Meyle) that came without the frame and it didn't fit; slightly too long. Caused a headache with the parts vendor because the stock photo showed the frame, and the part number was correct. They sent a different one (Mahle) that had the frame and fit properly.

If you ever get in as deep as atl530, might could run new heavier-gauge wire for the blower circuit.

[kouks]

It fit just fine. Got it from Pelican Parts, not OE BMW brand, not Meyle either.

[Alpinerunner]

I want to confirm that it's usually the fan motor itself that will blow/melt a fuse. I just found a melted fuse (plastic fuse body also slightly melted). I'd prefer just to change the resistor, but will do the fan, too, if it's definitely the culprit. I also want to confirm that there is no filter somewhere else if my car doesn't have one in the lower center console (footwell). I have a 7/90 early '91 M5 and I went to replace the cabin filter a year ago, took apart all that trim, and alas there was no filter housing at all!

[E38740iMD]

early e34 did not have the filter. mine didnt have it either

- - - Updated - - -

your car may have a sword instead of a blower resistor as well

[Alpinerunner]

early e34 did not have the filter. mine didnt have it either

- - - Updated - - -

your car may have a sword instead of a blower resistor as well

I've read that the sword was up to build date of January 1990. I'm a July 1990 build. I have found and extracted the resistor. Not possible to have both, right?

[E38740iMD]

not possible to have both. as they both serve the same funtion. i dont have a resistor but a sword. my car is a 07/89 which make sense. i forgot the build date where they start using the cabin filter