I never bothered to find where the various switch leads went once they entered the bundle. I simply went to the aft end of the engine (6LPA-STP) where I found all the color coded switch wires as indicated in the engine manual drawings and sent new wires from there to the console for my new alarm panel. Teeing into them rather than cutting them and butt connecting to the new wire ensured the original buzzer setup still worked. Properly placed diodes were needed to ensure all the alarm lights did not all come on at once.
Some ideas for troubleshooting:
Don't trust the oil pressure gauge. A manual gauge connected directly to the engine will tell the truth of that matter.
Once you are certain you have oil pressure, removing the wire from the low oil pressure switch, which is normally closed, with the engine shutdown but with ignition on would normally silence the low oil alarm. No other alarm should be on in this condition, but if it STILL sounds, go to the other switches one at a time and disconnect them until the alarm stops - there's your problem switch. Start the engine just to be sure. If buzzing does not stop with all the switches disconnected, there is a fault in the wiring at the buzzer.
With low oil pressure switch disconnected, if you don't get an alarm until the engine is started, you are back to disconnecting the switches one at a time to find the source.
If you find the source is the low coolant switch, but there is plenty of coolant, that switch needs attention. If you find the source is from the gear oil temp switch (and of course, it is not spinning and so is not hot), that switch is bad - same for the high coolant temp switch.
If you find the source is the water-in-fuel sensor, well, that's a bit harder to figure out because you may well have water in the fuel. If a check upstream at a Racor filter bowl indicates no water, and the engine runs fine, that sensor is bad.
So far that checks off low oil pressure, low coolant level, high coolant temp, high gear temp, and water-in-fuel, and that's about it unless a boost switch option is fitted.