Buggies Gone Wild Golf Cart Forum - HD 1979-1981 MG IV arcing when connecting negative terminal.

I have a HD 1979-1981 MG IV . It was in pretty rough shape but I had it running a few days ago. It wasn't getting full voltage to the motor in 4th gear so I started by taking apart the left and right motor diodes, the speed switch and wiper arm assembly. I tested all the components and I am pretty sure they all were good. I had already checked all the solenoids and they are good . Once finished I cleaned them all up (lots of corrosion) and reassembled per the wiring diagram on the other post, I also have the service manual. Now when I go to reconnect the negative battery terminal on the right side of the cart I get a major arc. I'm just looking or any help as to what the issue could be. So far I have literally checked the wiring 6 times. All wires are intact and connected to the correct places. No broken connections or accidental grounds. When I disconnect the wires going to left side motor diode, the arc does not happen. Is it possible that diode is bad or blew when I reconnected everything? Any help or next steps are greatly appreciated!