Fuse 20 blown repeatedly - burning smell in car

[Kalimsnor]

Hi guys!

I have a 325e 1984. About aweek ago the car started to smell heavily of something burning while I was driving. I immediately pulled over to see if I could find out what was going on, and then noticed that the heater / air conditioning was no longer working. No air at all and the lights were also off. The fuse turned out to be blown, so I replaced it (30A). Now this happened again yesterday (a week later) and I just put in a 20a fuse so I can try to figure out when this is happening. Seems like both times now it happened while the car was idle with the heater on.

I also checked all other fuses (since there's a few related to the aux fan) and all of them were a-okay. The aux fan also seems to run fine. Also checked coolant level (thought maybe that was the burning smell), but it seems to have stayed the same.

So its about this fuse:
# 20 - 30a - Heater / Air conditioner
Auxiliary Radiator cooling fan

Has anyone experienced this before? Or know what to do? I don't want my baby to burn down

Greetings!

[Brianmoooore]

Take out the heater fan motor and check if it turns freely. The motor has plain porous bronze bearings which dry out over time, partially or totally seize, and increase the current drawn by the circuit.
Note that fuse 20 is only concerned with the heater fan and the aircon. control circuits, not the auxiliary fan itself.

[Kalimsnor]

Take out the heater fan motor and check if it turns freely. The motor has plain porous bronze bearings which dry out over time, partially or totally seize, and increase the current drawn by the circuit.
Note that fuse 20 is only concerned with the heater fan and the aircon. control circuits, not the auxiliary fan itself.

You were right! Some WD40 fixed the issue altogether. Thanks a lot!

[Ukhozi]

The WD40 will only fix it temporally, best to strip it, sort out bearings, copper grease .

[Brianmoooore]

WD40 is only part of the fix. You need to remove the motor and fan completely from the car, hold the motor with its shaft vertically, put drops of light oil on the bearings, then power up the motor with a 12 volt battery. Disconnect the battery, turn the motor the other way up, add more oil, power up again, and repeat several times, until the oil has worked its way well into the porous bearings.

[Bonymaenjack]

WD40 is only part of the fix. You need to remove the motor and fan completely from the car, hold the motor with its shaft vertically, put drops of light oil on the bearings, then power up the motor with a 12 volt battery. Disconnect the battery, turn the motor the other way up, add more oil, power up again, and repeat several times, until the oil has worked its way well into the porous bearings.

Just to add WD40 is not a lubricant but a solvent , a temporary fix but just that, temporary

[Kalimsnor]

Thanks a bunch guys. I'll get to that next time I open it up and take it apart. I'm happy the blowers also blow a WHOLE lot more now with the WD40, but I understand it's just temporary until it all locks up again.

[Brianmoooore]

That's a bit like draining the oil from your engine when giving it a service, then driving it around for a it, before adding the new oil.