My Deere 160C lc excavator has set for awhile. When started it fired right up and still does. The problem is the engine oil pressure light come on and the alarm buzzes. So, I drained the oil and put on new oil filter and drained and put new oil in. I also replaced the oil pressure sensor with a new anew one. The problem still exists with a buzzing pressure alarm and red oil pressure light whenever I start it.
Will the alarm sound with the wire off the oil pressure switch? Put a gauge into the oil pressure switch port to confirm whether you have oil pressure or not. If the oil pressure is good, then most likely the wire to the oil pressure switch is shorted to ground somewhere. Oil pressure switch supplies a ground to the monitor when there is no oil pressure.