I don't know about a 190 but I had the same issue with snow and my 300D. Under a rubber cover, there is a bolt that secures the wiper arm. It had worked loose and only had to be torqued down a bit.

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Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/showthread.php?t=296386