It may be the switched relay. And if I can find mine, I'd verify that. But a similar problem on the CT335 was corrected by replacing that relay. I have no work lights, no gauges and no headlights but they didn't all quite at once. The work lights circuit quit first but I still had headlights after that. A few hours later I lost headlights and gauges and I'm under the impression it's the switched relay. On the CT335 it's on the firewall on left side of the tractor right between the fuel sender and the Operating Control Unit. On ours, I believe it's behind the dash.