Hi, I have the same problem, and the electric furl pump can not run. At end, I make a new ground negativ directly at the electric pump, and all is OK. I don’t where is the problem before, I chek all parts, and at end only the negativ don’t be correct at the electric fuel pump. I write from panama, and here many sellers and nobody to help you for Hisun.
the problem, it’s difficult to found a repair service manual for Hisun 500 ES year 2018
It’s very easy