One wiper arm not working

[2wagonhos]

I lifted my wipers up to wash my 1988 325iS and I accidently moved the drivers side wiper too far. When I went to put it back in place, it went, but when I turned the wipers on, only the passenger side worked. Did I strip the bolt? The wiper arm moves REALLY easily making me think that I stripped the bolt. Please help....

[abelai]

Take the arm off and see if the spindle is moving.

[Brianmoooore]

If one wiper is working, and the other not, then either the wiper has worked loose on its spindle, or the linkage has broken/fallen apart.
If the wiper makes a feeble attempt to move, then it's the former. If it makes no attempt at all, it's the latter.
Assuming your car is LH drive, it will have a completely different linkage assembly from most of us on here, so experience of your particular fault will be limited.
Take off the plastic grills (heater air intakes) on the scuttle and have a look.
These are removed by sliding them downwards a few milimetres, and then lifting them outwards at the top edge.

[2wagonhos]

Thanks guys for the help. It turns out the screw was loose under the plastic cab. Once I removed the cap and tightened the screw, it works perfectly. I did the same thing to the other side. THANKS!