I had a front wiper coming on without being selected, and the problem
apparently was the connection to the rear wiper motor, so I pulled the
cover and had a look, and it does corrode, as well, the rubber grommet
under the arm, lets water in. so silicone the grommet in, and check
the connection and if corroded, there is a plastic cover that comes
off the motor, and it will be corroded also.