Why does the motor need protection?
The motor is in a bad position. It's sat in a bucket that can fill up with water.
Also, it's sat right underneath a vent so rain can hit the motor directly.
The water can seep into the case causing rust and short circuits. Step 1 is waterproofing the case.
Step 2 is to add some more direct protection. Let's make a rain shield.
You don't need to remove the wiper mechanism from the car.
Remove the 13mm nut from the wiper crank.
Pop the wiper arm linkages off of the crank. Remove the 3x 10mm bolts and remove the motor.
Pull off the crank arm so you just have the bare motor. Now find a plastic bottle.
It just needs to be big enough to get the motor inside.
A 2 litre squash bottle or 2.5 litre fizzy drink bottle are about the right size.
Cut each end off the bottle and slide the motor in. Mark the main shaft with a pen and make a hole.
Push the shaft through the hole and mark the 3 bolt holes. Again, cut these out.
A soldering iron makes nice clean holes if you don't have a scalpel.
Fit the motor back into the mechanism.
Reconnect the motor, run it and turn it off. Line up the wipers, replace the wiper motor crank and tighten it down.
Refit the wiper arm linkages and test the wipers move the way they should.