Heater blower resistor 318i touring 1990

Mon Jan 05, 2015 8:42 pm

Wonder if anybody can advise me on locating the resistor.

I changed the blower motor early last year as the old one was noisy. The noise was cured but I still could only get the motor to work on two of the settings.

So last year I researched E30 wikipedia and dropped the glove box and panels, stuck my head right underneath, but couldn't see or feel anything that matched the photo on wikipedia of the resistor. So as I had two active settings I settled for this and put everything back as it was.

Unfortunately now all the settings don't work so I have no blower at all. So I dropped the glove box and panels again today in a hope that I might find the resistor this time... But I didn't !

I suppose it could be something simple like the fuse... Would the blower motor have a shared fuse, so that I can check if that other item works ?

Any advice appreciated...... Thanks.

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Mon Jan 05, 2015 8:47 pm

Just looked at wikipedia again and found that it's not a shared fuse..... Fuse 20.... 30 amp.... I'll check that first.

Mon Jan 05, 2015 10:16 pm

The resistor is the brown square here:

Removing the glovebox might gain you access, but you might also need to loosen up the centre console as well to see it properly. I can't help further as my car is LHD.

But if your blower was intermittent and is now dead, it's either that resistor or the fan itself. If so, remove the access panel in the engine bay, remove the fan and lubricate it properly before refitting.

Tue Jan 06, 2015 4:53 pm

Thanks for your reply Grrrmachine.

It was third time lucky. Pulled it all apart again and found it. Very hard to find. Although you get access from the passenger footwell, the resistor is located in an 'almost centre' position under the dashboard.

Cheers.

Tue Jan 13, 2015 4:57 pm

Just before my blower motor problem started, the blower worked on 1, 3 & 4. Then suddenly the blower didn't work on any settings, but you could hear a very slight click if you put it on 4.
So this is when I decided to locate & change the resistor. I eventually found it and replaced it with a new genuine BMW part. The blower still didn't work on any settings, so I thought perhaps the motor had packed up. So I took the motor out and tested it. I worked when I connected it up to 12v. The fans on the motor seemed a bit tight when I tried to spin them manually, so I oiled it up as best I could and it does now seem easier to turn. I checked that power was getting to the motor terminal and it was.
When I put it back together the blower worked initially only on 4, then 3 kicked in for a while. Then 3 stopped and now I can only get power on 4.
Any suggestions ? Could it be the switch? Are they known for becoming faulty and how do you get the switch out of the dash? Perhaps then I could test it.
Thanks again.

Tue Jan 13, 2015 5:34 pm

Sounds like the bushes need a proper clean and grease. Same thing happened to mine and was cured with a lot of cleaning and re greasing.

Tue Jan 13, 2015 6:58 pm

Never seen a dud speed switch yet! As HS says, the lubrication job needs to be done properly, which invariably means taking the motor right out of the car, connecting it up to an external 12 volt supply and holding it with the shaft vertical, while you clean out the bearings with something like WD40, and lubricate them with a light oil, like 3 in 1.

Tue Jan 13, 2015 7:07 pm

Sorry but I don't understand, if I'm getting power on 4, then why could the motor be the problem?

If that was the case, why work on 4 but not the other three speeds?

I did take the motor right out of the car and ran WD40 on the bushes whilst it was powered up.

Thanks for your replies so far.... Please send more !

Tue Jan 13, 2015 7:25 pm

There's more torque available in position 4, to overcome the friction from the partly seized bearings. If you fitted a new resistor pack before servicing the motor, you may well have damaged it. The resistor packs don't fail for no reason - they fail because of a faulty motor.

Tue Jan 13, 2015 7:29 pm

Ah !.... I see.

Appreciate your help.

Thu Jan 29, 2015 7:28 pm

hi from mike , normally its the heater resistor that's at fault , if it is only working on no 4 , there is a panel just behind the engine , take that off and you will see the resistor easy to pull out and change .

Fri Jan 30, 2015 2:33 pm

I had this issue and so I just pulled my heater resistor out through the passenger footwell, wasn't hard to do.

Looked a bit grubby, gave it a clean with some WD40, sandpaper and a fine wire brush, whacked it back in for all 4 fan speeds.

Although my fan had a slight squeak on 1 or 2 so it will need to come out to be lubricated eventually.

Wed Feb 11, 2015 4:20 am

Thank you very much for all replied. Very useful thread. My fan motor also started squeeking. Will give it a good clean and lub.

I heard from somewhere that if the clean & lub don't help, then bearings in the motor can be replaced to cure the issue. Has anyone done this or in this you went for a full replacement of motor?