Wiper Arms...which is which

I took my wiper arms off to spray them black since they had plenty of surface rust. I am now wondering which is which. I know the driver's side has the longer blade...but which side has the longer arm.

One of the arms has this plastic black pad on it with 2 little screws (not sure if that is the driver or passenger side arm) . What on earth is that thing anyways?

 

[Terry Posten]

The "pad" is a wind deflector and that is the drivers side.

 

Thanks

 

[fuel]

the passenger wiper arm will also have a 'P' embossed on to it where it attaches to the spindles.