It could be a micro switch, forward and reverse switch contacts or a bad cable connection. I doubt if its the controller, on a series cart the controller doesn't control the direction like it does on a regen cart.
well this has me by the short hairs. everything seems right I've tried everything, micro switches, new controller every test. Everything comes up good. No reverse unless, we change the black and white wires on the controller.
I didn't realize this was a DCS cart I don't think you mentioned that. The micro switches are easy to test with a Ohm meter. If the micro switches are both good then it's probably the controller causing the problem, or possibly not wired correctly.