Our wipers have been on the long slow decline, and last week, they finally gave up.

At first, we could turn on the wipers but not select the speed.
Eventually, we couldn't turn off the wipers at all without pulling the fuse.
Now, we can squirt the washer, but can't turn on the wipers at all.

We have a friend who thinks it might be a relay. Does anyone know how we should go about diagnosing the problem?

 

Could be the switch as well.