My two decade plus old Kubota L3240 HST broke down in a steep canyon where I had to abandon it for a week. I wanted to avoid the expense of paying for a Kubota technician’s field service trip to trouble shoot it. I read on this forum about others with a chronic blowing of the main 50 amp fuse. I learned here that I can bench test the four relays under the instrument bezel. Many You Tube videos for that. The relays all checked out fine. Next I read a post where mice had ate through some wires causing the main fuse to blow. After searching along the wiring loom I found and repaired the rodent damage about 3 inches off the positive battery cable on a secondary wire. Some models have a fusible link at that location but mine appeared to just be a plug-in connector.