'67 Harley Electric won't go forward

[BajaBreny]

Have had my '67 HD 36 volt electric cart for 10 years with very few issues. I don't drive it more than 500 or so yards in a single day, and more likely less than 100. Have 6 recently purchased batteries. I was out of town when GF drove it til it wouldn't go forward anymore. Not sure what happened since I wasn't present. We live in Baja Mexico, at the beach 40 minutes south of San Diego so have to rely on a few local mechanics who have limited experience with old electric golf carts. However one local elderly guy rebuilt the motor a couple of years ago and it worked like a charm. Probably have not put more than 20 hours on the motor since the overhaul. Now with new batteries its not moving. Replaced a solenoid pursuant to one suggestion and now I have reverse. Yes we swapped out the forward/reverse switch as well, again only reverse. Any ideas? thnks