Temperature Warning Lamp/Indicator: Testing and Inspection

Chart C-16:

Wiring Diagram For Warning Light:

CIRCUIT DESCRIPTION:

The "TEMP" light or optional "CHECK GAUGES" light, is connected to battery voltage through the ignition switch. The ECM energizes the bulb by suppling a path to ground through a quad-driver module number two.


TEST DESCRIPTION: The numbers below refer to the circled numbers on the diagnostic chart.

1. With the ignition energized and the engine not running, the ECM should be grounding circuit 35.
2. While the engine is running, the "TEMP" light or optional "CHECK GAUGES" light should be turned "ON" by the ECM only when the coolant temperature is above 123°C (253°F). The "TEMP" light or "CHECK GAUGES" light should be "OFF" when the coolant temperature is lower than 120°C (2490°F).

DIAGNOSTIC AIDS:

The coolant temperature sensor, in rare cases, may fail to indicate the correct engine coolant temperature without setting a malfunction code. This could result in energizing the "TEMP" light or optional "CHECK GAUGES" light without having an overheating condition. It could also result in overheating without the "TEMP"/"CHECK GAUGES" warning light being energized.