Yup, even the washer fluid switched +12v feed goes from the MFS, to the wiper motor assembly, then to the pump. So it's very possible your issue is with that.
There was some problems with early build 2003s, like yours, having wire harness chaffing issues around the wiper cowl. Inspect the wiring in this area as well.
-'03 MB SL55 AMG (toy) -'08 MB GLK350 (d/d) -'95 Mark VIII (under renovations) -'02 Navigator ("beater")
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