2003 oil sensor question

I have a 90TLRB with oil injection and no gauges, just the alarm buzzer. The buzzer would go off when the key was turned on. The engine would start but the buzzer wouldn't stop. With the engine not running, the only things that could set off the alarm are engine temp and and the oil level sensor in the internal tank. Pulling the connector for the oil sensor stopped the alarm, so I replaced the sensor (my service manual hadn't arrived yet). That didn't fix the problem, and checking the sensors when I got my manual showed that both were working.

Further troubleshooting showed that the sensor would alarm when the float was at the low point (low oil), as expected. What surprised me was that the alarm would go off when the float was at the top (oil full), but ti sounded a little different. I am concerned about low oil, so I put a couple of tie wraps around the sensor to keep the float from going all the way to the top. Now the alarm doesn't go off unless the oil is low.

So my first question is this: Why would the alarm go off if the oil is full?

My second question is this: The service manual just shows the oil sensor wiring. It does not show what the oil sensor connector connects to. I traced the wiring and it goes to the trim sensor. Why would it do that?

My third question: An admin on another forum suggested disconnecting the oil sensor. Doing that would not give me the low oil alarm as far as I can tell (and this bears out based on my testing). Any ideas why anyone would do that, other than to just shut off the alarm and forcing you to visually verify your oil level?

Replace the buzzer !!

I don't see how the buzzer could be the problem. The alarm goes off when the pink wire is held low (grounded). I checked the engine-side of the harness connector and verified that the pink wire is grounded. And, when I manually move the float on the sensor, the buzzer operates properly, other than buzzing when the float is at the top of the sensor.