Yanmar Oil Pressure Light/Alarm Out? Please help!

[gwp]

1986 2GM20F
Can someone give me some ideas as to why, all of a sudden, when I turn the key to the "on" position, the oil pressure alarm doesn't sound nor the light come on? I'm pretty sure the sending unit is designed as normally closed, and it is grounded properly. When I throw the test switch, the alarm sounds and the "charge" light comes on. Trying to help a friend. Any help very much appreciated!

[badsanta]

if it worked before and now not. I would check the fuses and ground. There may be some inline fuses buried in the wiring harness next to the engine