Motor brake failure, seen this too many times. Only use the OEM "standard duty" brake. Not the OEM HD brake, and run from any aftermarket brake. Danaher controller doesn't play nice with any others. The OEM will come in a "Pro-fit" label, that's what Ezgo does now.
Here's a thread I wrote about this topic.
http://www.buggiesgonewild.com/elect...xv-brakes.html