Hello,
After updating firmware of Vive Tracker 2018, my haptic motor connected with Vive Tracker did not come to work.
After a couple of days researching, I found this page and my issue is completely same as this.
I checked out output pin voltage and it was 0.3V, not 3.3V.
I replaced with old Vive Tracker and it worked perfect.
So, it is clear that the firmware update has issue and would like to fix it.