EDIT: You may have a "Short" in the wiring...Only way to tell is Look and
probe with a Multimeter.
No Short? See Below:
The brushes are worn (AND when they do ,the Motor "Pulls" more amps)
OR the Bearing(s) are going (SAME Effect , Although the Motor IS Working
Harder to push the Bad bearing(s),Which Pulls more Amps)
'Are you Handy ? (As in a "Crazed" DIYer like many of us here)
I've reposted the pictures...they didn't survive.
Post of a Member who Re-Bearing-ed his (AND offers to do yours) :
http://www.peachparts.com/shopforum/showthread.php?t=98493&highlight=Bosch+Aux+Fan+Bearing%2FRebuilt
(ALL the Fans are similar ,appearances may vary)
(I've not investigated a source for the brushes...)