1998 Ford Explorer Temp guage

TEMPERATURE GAUGE TEST
Turn ignition off. Disconnect temperature sensor harness connector. Connect Instrument Gauge System Tester (014-R1063) to temperature sensor harness connector Red/White wire. Set tester at 300 ohms. Turn ignition on, wait 60 seconds and read gauge. Temperature gauge should read cold. Turn ignition switch off. Set tester to 45 ohms.
Turn ignition switch on, wait 60 seconds. Temperature gauge should read one quarter to mid range. Turn ignition switch off. Set tester to 18 ohms. Turn ignition switch on, wait 60 seconds. Temperature gauge should read hot. If temperature gauge does not function as specified, replace gauge.

COOLANT TEMPERATURE GAUGE INACCURATE
Perform TEMPERATURE GAUGE TEST under COMPONENT TESTS. If temperature gauge performs properly, replace temperature indicator sender unit and retest system. If temperature gauge does not perform properly, go to next step.
Turn ignition switch off. Disconnect temperature indicator sender unit harness connector. Remove instrument cluster. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. Disconnect instrument cluster connector C287. See Fig. 2. Measure resistance of Red/White wire between instrument cluster connector C287 terminal No. 3 and temperature indicator sender unit harness connector. Resistance should be less than 5 ohms. Measure resistance between ground and instrument cluster connector C287 terminal No. 3 (Red/White wire). Resistance should be more than 10 k/ohms. If resistance is as specified, go to next step. If resistance is not as specified, repair open or short in Red/White wire and retest system.
Disconnect instrument cluster connector C288. See Fig. 4. Turn ignition switch on. Measure voltage between ground and instrument cluster connector C288 terminal No. 1 (Red/Yellow wire). If voltage is more than 10 volts, go to next step. If voltage is less than 10 volts, repair open in Red/Yellow wire between instrument cluster connector and fuse No. 11 in interior fuse panel and retest system.
Turn ignition switch off. Measure resistance between ground and instrument cluster connector C287 terminal No. 2 (Black/White wire). If resistance is less than 5 ohms, go to next step. If resistance is more than 5 ohms, repair open in Black/White wire between instrument cluster connector and ground and retest system.
Measure resistance between instrument cluster temperature gauge clips "B" and "S". Resistance should be 215-256 ohms. Measure resistance between instrument cluster temperature gauge clips "G" and "S". Resistance should be 90-110 ohms. If resistances are as specified, replace instrument cluster printed circuit and retest system. See PRINTED CIRCUIT under REMOVAL & INSTALLATION. If resistances are not as specified, replace temperature gauge and retest system.