Wow!!! Our new-to-us Sector 750, with only 84.4 hours, is doing exactly the same thing. When you turn the ignition key, the EPS turns hard all the way to the left.
I am in discussion with "Chris" from HISUN . . . I have his email and phone number . . . and with the original selling dealer.
I have sent a short video clip to both of them, showing what happens when I turn the key.
There is no dealer convenient to us and "taking it in" would involve renting a UHaul carhauler. I have also read horror stories from people who took their HISUN in to a dealer to get a defect fixed.
I'm treating it as a consumer product safety defect, and have reported it to the Consumer Product Safety Commission . . . 20240920-18A7C-2147336406 .
I stumbled onto this thread when I searched if a HISUN can operate with the EPS disconnected.
Our previous UTV, a 2008 Bush Hog TH440, was not a pretty thing, but it was not a death trap!!!!!!