The blower fan quit working on the 96 E300 diesel,w210,I know its a common issue,however,before I try to get a used one or a replacement from ebay,is there any way you can get the fan to work on one speed continuosly...its kind of cold right now without fan at all,any input in how to diagnose if its the fan himself(less likely) or the regulator and where to get the most inexpensive part will be appreciated...

To check the motor, apply voltage from the regulator input to the motor itself. It should howl. You probably don't want to drive with the fan motor connected to 12V. If I had this problem, I might find a power resister to limit the current. But I'd probably either get a 140 regulator, or build my own.