Heater Blower not working - FIXED

[Arfcollins]

Several electrical problems had hit me at the same, I feared the worst but they turned out to be unrelated.

The heater blower fan had packed up, after behaving sporadically for a few days. I checked the resistor pack which was very corroded, there's obviously rain water getting in down there. That was my only waste of money, 40 odd quid, as the replacement made no difference.

At that point I borrowed a meter and found that the power was getting to the motor, just not doing anything when it got there. So out came the motor as I thought the brushes may be dodgy. Easy enough to get out though you need to be a bit of a contortionist. 

There are two small bolts to remove on the motor casing then you can ease it off. I took off one of the brush housing caps by levering with a small screwdriver and found there was plenty of meat on it. The commutator was filthy though, with black carbon deposits on the surface but also bridging the segments. I cleaned the surface by scraping gently and used a 0.5thou feeler gauge to cut through the hard deposits between the segments. A quick suck with my wife's new hand held vacuum cleaner finished the job.

And the fan now works perfectly. On the mid setting I can't hear it over the engine noise, so I can't help myself but turn it up to full from time to time to check it's still working. Was without the fan for a good while and hadn't before then realised how essential it was to warming the car and windscreen.

The debris had obviously been building up for some time, and the fan was sometimes noisy, which I think may have been from shorting between the coils, giving irregular impulses. I thought sometimes the noise was due to a trapped leaf (something my old Volvo suffered from) but now I think it was the dirt causing it. 

Hoping this is a real fix, will let you know if it isn't.

[ffrenchie]

In our M59 I always leave the fan running on its lowest setting so it comes in as soon as the key is turned. I've done this since fitting a couple of motors in my daughter's Corsa because they had seized while stood and she does the same and has had no further problems. Hope you have cured your problem for good.

[brodfather11]

When I was young I was given a blue tube 1/2" dia which was filled with fibre glass (I think) strands. Puzzling over what it was for I was told it was for cleaning commutators in a dynamo. Tried it out and it worked great .
Don't know if you can get those nowadays but a pen type tool for cleaning up old copper coins which has a fibre glass core instead of ink, would do the same job on a smaller scale .

[Arfcollins]

That rang a bell, I remember seeing one of those years ago but didn't know what it was for. Something similar still available.
http://www.rcmart.com/trinity-rc4053-com...-8719.html

[brodfather11]

That's the kind of thing , made a great job though I only tried it out ,don't think I ever had to use it for real as the alternators were starting to come in then. As your link says probably good for all dc motors or dynamos.