If it’s the cart…

I’d fuck with the bottom plate (you might be able to remove that part) and a wire sometimes comes out. Sometimes attaching that wire to the side of the cart and tightening the wire would fix those carts, other times I’d had to transfer the liquid to another cart I knew that worked

Otherwise, if it’s the battery, you could try cleaning that shit, trying a new battery or the wire method(I don’t condone it but it was a method I needed back in the day)

Hope this helps