HWH 210 series HYD pump motor not working

Update. I never heard back from HWH after emailing them. Called several RV places for parts numbers they called HWH but they wanted an AP number which I did not have. So I took the motor apart to see if anything looked bad. Brushes looked good there was continuity between the positive brushes and the positive post. The inside cap was rusted so I cleaned that up and got continuity between the negative brushes and the outside end cap. The motor is internally grounded. Also got continuity between each end cap and the bolts that hold the motor together. Hooked the battery to it and nothing. A guy who rebuilds motors called me back several days later and in two days he fixed it. He ended up putting a bolt through the negative plate inside the motor to the outside so I could externally ground the motor to the frame. $101 later my jacks work again. Still can’t figure out why the internal ground path did not work. I noticed most of the replacement motors had this external ground stud so you can ground to the frame.