As soon as I replace the fuse for the radiator fan in my 2003 CLK Cabriolet, the fan will run for several seconds, then the fuse blows.
Any suggestions?

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) :
Bosch Aux Fan - New Bearing/Rebuilt - 123 Body

(ALL the Fans are similar ,appearances may vary)
(I've not investigated a source for the brushes...)

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'84 300SD sold
124.128