TUBE AS 1873228 - Caterpillar

Step 1. CHECK FOR OPEN FUEL PRESSURE SWITCH
Disconnect the signal wire from the fuel pressure switch.
Touch the signal wire to the other switch terminal (frame ground).Expected Result:Horn no longer sounds.Results:
OK - The fuel pressure switch is open. Go to Test Step 2.STOP
NOT OK - The harness circuit (signal or ground) is open. Go to Test Step 3.STOPTest Step 2. CHECK FOR FUEL PRESSURE SWITCH
Check for fuel pressure.
Check for plugged filter inside the switch.
Check for faulty switch.Expected Result:The fuel pressure switch should be closed when fuel pressure is below the specified value.Results:
OK - The fuel pressure switch is closed when fuel pressure is below the specified value. Go to Test Step 3.STOP
NOT OK - The fuel pressure switch is not closed when fuel pressure is below the specified value. Go to Test Step 3.STOPTest Step 3. CHECK FOR EMS Control
Using a 7X-1710 Multimeter Probe, place a jumper from contact 13 to contact 2 at the machine harness connector for the EMS control. Do not remove the connector from the control.Expected Result:Horn no longer sounds.Results:
OK - The harness circuit is open.Repair: Repair or replace the harness.STOP
NOT OK - EMS control is faulty.Repair: Replace the EMS control. See EMS Control Replacement.STOP