Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Remove leads from air pressure switch (make a note of their location)
Remove X16 from the PCB
Remove X16 from the PCB
Measurement:
Measure the resistance of the wiring harness from the red leads of X16 connector to the disconnected leads at the air pressure switch.
Expect continuity / zero resistance on each wire.
Also visually inspect the condition of the wiring and connectors.
Note.
Ensure a good connection is made during resistance tests.
Expect continuity / zero resistance on each wire.
Also visually inspect the condition of the wiring and connectors.
Note.
Ensure a good connection is made during resistance tests.
Isolate as per TOPs P4
and refit as necessary