Glow Plug System: Testing and Inspection

Glow Control System Check [Except 12,000 lbs GVW]

Description
The glow control system consists of the engine control module (ECM), the glow relay, glow plugs and the glow indicator lamp. The glow control system is operated when the engine coolant temperature is low, which allows easier engine starting. If the ignition switch is turned ON when the engine coolant temperature is low, the ECM turns ON the glow relay and illuminates the glow indicator lamp. After a fixed time passes, the ECM turns OFF the glow relay and the glow indicator lamp.

Glow Control Operation
- The glow control system operates when the engine coolant temperature is less than 50 °F (10 °C).
- The glow indicator lamp is illuminated between 3 seconds and 10 seconds according to the engine coolant temperature.
- The glow relay is ON between 15 seconds and 30 seconds according to the engine coolant temperature.

Glow Control System Check [Except 12,000 lbs GVW]
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views


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