Remove the blower and the resistor, and then test the blower with your battery. If the blower works, then it is your resistor, and you can find them online. Your best bet is to replace both units. It is very easy to replace in under mins, once you have the right tools.
It is more affordable to replace the blower regulator only - which is best found as a regulator for a W140 - here in US eBay is a good source.
MB later "updated" both the blower and regulator for the W210 - so a "updated" W210 regulator requires a updated blower - but using the W140 regulator and just extending the leads is the most affordable fix.
I used a 6v lantern battery to test my blower motor - the car battery carries a huge amount of amp capacity that could damage the blower motor with a direct hookup.
+1 on the W140 regulator - there is a post in the stickies on how to splice it in. That was the route I went. I believe there may even be an update to that post on a part number regulator that does not need to be spliced.
BenzWorld.org forum is one of the largest Mercedes-Benz owner websites offering the most comprehensive collection of Mercedes-Benz information anywhere in the world. The site includes MB Forums, News, Galleries, Publications, Classifieds, Events and much more!