I should correct this. The word I should have used instead of disconnected is BYPASS.
You can't disconnect the shift assist switch to test it. You have to install a bypass jumper.
To check the main circuit breaker. You put both wires on one of the posts.
Vessel View will only give you codes. Your problem will most likely need more info than just codes.
Vessel view gives you each and every fault and description....but you need to log in. If you aren’t logged in or have not registered...then it’s only codes.
All the best.