Hello again,
There is no other ground for the wiper motor, that's it. Okay let's work on the power side of the circuit. With the ignition switch turned to the "run" position, and the wiper switch turned on, can you please take a voltage reading for me at the A pin of the wiper motor electrical connector. It is the pin with the red wire going into it. You will have to use a Digital Multi-meter [DMM] to do this, so here is a link explaining how they work below, if you are unfamiliar with them:
https://www.2carpros.com/articles/how-to-use-a-voltmeter
Please report back here with what your reading is and we will go from there.
Thanks,
Alex
2CarPros
Nov 5, 2019 at 5:35 PM