1989 Ezgo gas, starts and runs in forward, no starter spin revers

[nerdmann_21]

I have been trying to figure out what is going on with a cart I picked up last fall. The motor will spin and start in forward with no problems. when I switch to reverse the solenoid clicks but the motor won't spin. If I work the peddle for a few pumps sometimes it will spin and starts. Most of the time its just a hum or weak like the starter motor isn't getting the power it needs. I was thinking it was the solenoid, I replaced, still have same issue. I took the main fwd\reverse switch apart and cleaned the contacts, all looked good there. I have been tracing the wiring and everything looks correct to the schematic. One thing to note is the reverse horn will not stop busing. it was unplugged and when I plug it in the solenoid it buzzes no matter the position. What are the next things I should look at?

[cart around]

The horn is wired to the hot side of the key switch and has its own microswitch mounted on the driver's side of the FnR switch. I would say it is stuck closed.

For the other problem, start with looking at the brushes.