I have a New Holland 3630 and the electronics are totally dead on it. The voltmeter shows 12 volts on the battery and the monitors that are connected directly to the battery operate normally.
I have had problems with electronics for a while. the brake warning light and buzzer come on at random times. There have been times when the dashboard lights went out for a second and then came back on and everything worked fine. Just before everything was completely turned off, some lights on the dash came on and then went off again.
I can’t imagine the fuses being the problem since the dash lights have always come back on in the past, but I will check them.
You may have a pair of inline fuses on the battery cable connectors – it’s a bad place to have them due to corrosion
which always seems to happen next to the battery. I would suggest removing and cleaning the battery connections both positive and negative.
Then follow the main harness to the dash, disconnecting, cleaning, and oiling each connector all the way to the back of the dash.