This boat has an OMC Systems Control gauge on it. The problem is the no oil light will come on, the buzzer will sound for ten seconds and then stop but the light stays on. The VRO is still pumping oil as indicated by the exhaust & the level in the reservoir. I have been told it could be the blocking diode in the harness. Any ideas??? The light on the gauge originally would come on without the engine running. Turn the key to on, the gauge would go through the self test(each light comes on then goes out)then the no oil light back comes on and stays on.