G9-E suddenly stopped working

[Sno-twister76]

Hello all, I'm new to the forum and looking for advice on an issue with my elderly neighbors electric golf cart. It is a Yamaha G9-E, not exactly sure of the year but guess early 90's. They use this cart daily around the yard. The other day it just suddenly stopped while driving to the house. I have checked the main battery voltage and it is at 36v. There is no click from the solenoid with the key on, in forward or reverse, and the accelerator pressed. I checked voltage to the solenoid on the coil terminals and only have barely 1 volt. So working backwards I find several connectors in the harness corroded. mainly the two diodes. One is so bad the diode broke trying to remove it. So what function do these diodes serve and where is there a part number for it? I also need the connector itself. Are these Packard style connectors?

I have the wiring diagram; battery voltage is good, fuse is good, main switch is good, F/N/R switch is good aside from the corroded terminals all wires are good. I just have a feeling there is something other than the connector issue here. Is there a test procedure for the controller? Any input would be appreciated.