Just attempted it on my car. Everything looked normal on mine cept for the nut that attacted the linkage to the motor was loose causing lots of play in the linkage. I manually concealed the passanger wiper and tightened that nut down and tested the wiper, concealed nicely. Put everything back together but while tapping the driver'* side wiper back on I broke something, it seems like the only thing holding the drivers side arm up is the wiper linkage itself. So now not only does my driver'* side wiper not work, but my passanger doesn't even conceal because of it!

So sorry to hear it'* worse now... I checked my partslist...
22093215 9-91 L SE Wiper Arm
I'm not sure if that'* it or not... but I hope it helps.