I am helping a widow lady with a non-functioning cart. I am a newby when it comes to these things, although I wrench all my cars. It does fine in reverse, with the buzzer working, but is completely dead in forward. She said that it worked intermittently, but on the day I was there it would not work at all. I think it is a 90’s DS 48 volt model. I thought sure it would be a bad forward/reverse switch so I removed it and took it home to inspect it. It tested okay with my DVM, but it did have some pitting on one of the forward contacts. So I took it apart and cleaned it and switched the worst looking forward lug to the reverse position. After reassembly I reinstalled it and there is no difference. Goes backward, but not forward. What should I check next?