98 C230 Heater blower motor issue.
 

C230 Blower motor was not functioning properly, as in not coming on at all. This started late fall 09. We accidently tapped the cover with feet while moving around on the passenger side and the blower came on. Without beating our otherwise nice condition interior to death, we came into the habit of tapping the cover to jump start the blower at random times. Kind of silly, I know. but it worked and the problem didnt happen consistently, sometimes never. The other day, the blower failed entirely.

From my success in the past by posting here, I hope to head in the most proficient direction on this asap. I've analyzed my MB Service Repair Manual disc so I have a venue of avenues to take from that, nothing seems to difficult, however...
I'm asking what is the most common, or most likely cause of this statistically, or from anyones experience.
I would liek to beging with the most common known possible source if possible. There are a ton of "bad connection', "corroded or overheated terminal or connection" yada yada. I will inspect all of the A/c-HEAT circuitry as shown in the scematics and that should be an obvious find "IF" that's the problem. Could it be so simple? Possibly.

Input, Input ??? :P

Thanks in advace!
Christopher
Anchorage, AK

Electronic blower regulator is the most common failure followed by the motor itself.

Checking the voltage signals at the blower connector will tell.

I would have guessed the motor first (brushes) then the regulator, but I will not argue with MB DOC... I think the test is to look for voltage at the motor and if there is some then the motor is bad. If there is none then the regulator is bad. Another test would be to apply 12V directly to the motor and see if it spins.

Directions appreciated!
 

Thanks for the input regarding the blower issue.
This narrows it down a lot better for trouble shooting the problem.

I should have time to tackle it by weekend.
I'll post my findings and pass it on.

Regards,
Chris :)