Onan Generator is Dead

The Kohler Onan 5 kw unit on our 2014 R31 CB is not working. I turn on the power to it and the stern thruster and measure 12.8 volts at the main power leads but the onboard control display is blank and nothing happens when I try to start it inside the cabin or at the unit itself.

What steps would you take to diagnose the issue? I'm thinking it could be a relay or the control board.

I would check the fuses first. There should be fuse for the panel wiring.

Martin....are you talking about the fuse panel behind the helm in the V berth?

There should be fuses on the unit itself. There might be a small panel near the start button. Look for a manual for your particular unit.

I had a similar problem with a MASE generator. A fuse on the unit had vibrated loose. This was a 3 amp fuse to protect wiring to the remote panel. Panel was dark until I fixed the loose fuse.