W210 Blower Fan Intermittant

[MeanRedSpider]

The fan on my W210 is (as the title suggests) running intermittantly - mostly off. Any clues as to where I should start? The switch position makes no difference. Where can I access the fan motor from?

Thanks

Richard

 

[Shude]

There are a few things that can cause this.

Firstly take a look here: http://www.mbclub.co.uk/forums/howto/5482-howto-blower-motor-ventilation-fan-removal-w202.html

The 210 isn't exactly the same as the 202 but it'll be similar. My guess is that either the brushes are worn on the motor or the regulator/speed-controller is failing. It could also be a loose connection anywhere between the fan and the control unit in the dashboard but that's less likely than the first two options!

It'll take you about 15 minutes to get the fan out. If you find that flexing the plug in the socket on the side or simply squeezing the fan casing causes the fan to change speed then the brushes are worn (squeezing the casing pushes the brushes closer to the commutator). If you pop the clips off and take out the springs and brushes you'll be able to see how worn they are, not sure how long they should be but mine were literally a couple of mms long! Stretching out the springs to about 50% longer will give you probably another 6 months or a year more life out of the brushes, mine have been running for FIVE additional years now with the springs stretched and other objects squeezed in behind them inside the shafts!

If it's not the brushes but the speed controller then I'm afraid you'll probably need to get a new one, I believe there are a couple of different types and both are pretty expensive from the stealership parts counter so you might want to check out a breaker or two.

Please let us know how you get on! Good luck!

 

[MeanRedSpider]

Ta - I'll have a play this weekend

 

[MeanRedSpider]

OK - had a go at this - the instructioons are pretty much perfect except that the later model has Torx screws rather than clips on the outer cover.

The good news is that the motor is fine. Also, the fan is running from the switch again. The only odd thing is that the fan doesn't run when the ignition is switched on but only when you CHANGE the position of the blower speed switch. Any ideas? The switch seems to operate fine. How does the switch and fan controller work?

Cheers

Richard