F 150 4WD Pickup V8-5.4L SOHC VIN 3 (1999)
Temperature Gauge: Description and Operation
Engine coolant temperature information is received by the instrument cluster from the Powertrain Control Module (PCM) over the SCP network.
Temperatures over 121°C (275°F) will display hot (H). If the engine coolant temperature data is missing or invalid for five seconds, the instrument
cluster will move the engine coolant temperature gauge below the cold (C) position.