would be a good idea to include cart voltage when posting a question
Put the FNR switch in reverse, if You don't hear the buzzer the OBC is in lockout mode.
try Resetting the OBC
To reset the OBC the following must be done in this order:
• Key Switch to Off
• Forward/Reverse to Neutral
• Tow/Run Switch to Tow
• Disconnect the Battery NEGATIVE (–) wire from the Battery Minus terminal on the battery pack.
• Put the Tow/Run to Run
• Forward/Reverse Switch to Reverse
• Key Switch to On
• Lock the throttle pedal down, Leave the cart like that for 5 min to cause the OBC to reset.
To reconnect the OBC back into the system:
• Key Switch to Off
• Forward/Reverse Switch to Neutral
• Tow/Run switch to Tow
• Reconnect the Batt – wire to the battery minus terminal on the battery pack.
Once the OBC has been reset, the cart can be troubleshot.
There is always a chance the OBC has completely failed and the reset process will not fix the problem.
The way you know the OBC reset is the first time You go to drive the battery warning light will come ON.
Plug the charger IN and see if it works, if it does, unplug the charger and test the cart in reverse again.
If the reverse buzzer now works, the problem is definitely the MCOR micro-switch