Calibration Test (Without Tester)

Test temperature gauge with a 10-ohm resistor for high calibration, and a 73-ohm resistor for low calibration.
Turn ignition on and connect a 10-ohm resistor between gauge lead and ground. Temperature gauge pointer should read within band around "H" mark. Connect 73-ohm resistor in place of 10-ohm resistor.
Gauge should now read around "C" mark. If gauge readings are not as indicated, replace gauge and retest. If readings are as indicated, replace temperature sender.