Engine Coolant Temperature Reads Inaccurately
WARNING: This page is about a different car, the 1997 Mercury Cougar and 1997 Ford Thunderbird. However, it is still accessible from the selected car via links, so may be relevant.
- Turn ignition switch to OFF position. Disconnect temperature sensor connector. Connect Instrument Gauge System Tester (014-R1063) to temperature sensor connector. Set tester at 74 ohms. Turn ignition switch to RUN position, wait 60 seconds and read gauge. If gauge reads cold, go to next step. If gauge does not read cold, go to step 3).
- Turn ignition switch to OFF position. Set tester to 9.7 ohms. Turn ignition switch to RUN position, wait 60 seconds and read gauge. If gauge reads hot, replace temperature sending unit and retest. If gauge does not read hot, go to next step.
- Turn ignition switch to OFF position. Remove instrument cluster. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. Disconnect cluster connector C251. See Figure. Measure resistance between temperature sender connector Red/White wire and cluster connector C251, pin No. 8 (Red/White wire). If resistance is less than 5 ohms, go to next step. If resistance is more than 5 ohms, repair open in Red/White wire and retest system.
- Measure resistance of instrument cluster printed circuit between the indicated of printed circuit flex connection and terminals of gauge. See TEMPERATURE GAUGE CIRCUIT CHECK TABLE. If resistance is less than 5 ohms for each circuit, replace temperature gauge and retest system. See TEMPERATURE GAUGE under REMOVAL & INSTALLATION. If resistance is more than 5 ohms, replace printed circuit. See PRINTED CIRCUIT under REMOVAL & INSTALLATION.
TEMPERATURE GAUGE CIRCUIT CHECK
| Cluster Connector: Pin No. (Wire Color) | Gauge Terminal |
|---|---|
| C250-11 (RED/YEL) | B + |
| C251-9 (GRY/RED) | GND |
| C251-8 (RED/WHT) | SIG |