Temperature Sensor (Gauge): Testing and Inspection

Fuel Tank Analog Gauge
1. Disconnect wiring harness connector at sending unit and connect ohmmeter between ground terminal and resistor terminal on sending unit.
2. Meter should read 8---86 ohms. If reading shows no continuity (infinite reading), check ground connection to tank gauge.
3. If ground is satisfactory, but reading is not within specification, tank unit is defective.
4. If reading is within specification, remove fuel tank gauge from vehicle and connect ohmmeter between resistor terminal and ground terminal (metal housing on single terminal units).
5. Observe meter while slowly moving float rod between empty and full stops. Meter should read 60---86 ohms at empty stop and 8---12 ohms at full stop. Change in readings should be smooth, without hesitation or jumping.
6. If tank unit fails to operate as outlined, unit is defective. Before installing fuel tank gauge, connect wiring harness connector to gauge and move float rod from empty to full position with ignition key in ON position. If dash gauge reading is incorrect, check IVR and dash gauge. If system tests prove satisfactory, but system still does not operate correctly, check that tank gauge rod is not bent or binding and that float is not damaged, loose or filled with fuel.
Oil & Temperature Sending Units
1. Test dash gauge and IVR as outlined above.
2. If system is satisfactory, start engine and allow it to reach operating temperature.
3. If no reading is indicated on the gauge, check the sending unit-to-gauge wire by removing the wire from the sending unit and momentarily ground this wire to a clean, unpainted portion of the engine.
4. If the gauge still does not indicate, the wire is defective. Repair or replace the wire.
5. If grounding the new or repaired wire causes the dash gauge to indicate, the sending unit is faulty.