YES: Air filter restriction
switch has failed.
NO: Check harness.
Disconnect two harness leads from air filter restriction switch.
If indicator was ON, did it go OFF with leads disconnected and key switch ON?
If indicator was OFF, connect two harness leads together.
Does indicator come ON when key switch is ON?
FUEL GAUGE (P3)
YES: Gauge and gauge
resistor are OK. Go to
fuel level sensor (B8)
NO: Go to next check.
Disconnect 20-pin harness connector from monitor display and controller connector.
Connect 24 volts to 20-pin monitor display and controller pin 30.
Then ground pin 46.
Does gauge needle point to "E" with 24 volts applied to pin 30, and "F" with pin 46