YES: Go to next step.
NO: Check wire harness.
Disconnect harness from overload alarm pressure switch
With boom positioned at either side of excavator, turn key switch ON.
With voltmeter, measure voltage at pressure switch harness connector pin 3.
Is 24 volts measured?
Turn key switch OFF.
YES: Pressure switch has 9015
Connect jumper wire across pressure switch harness connector pins 1 and 4.
NO: Harness has failed.
Turn key switch ON.
Does overload alarm sound?