Glow Plugs
The glow plug system uses 4 glow plugs (heaters) to assist in cold starting. When engine coolant is below 86°F (30°C), No. 2 glow plug relay is energized to quickly heat glow plugs.
When the glow plug reaches maximum temperature, relay No. 1 is turned off and relay No. 2 provides a reduced voltage to maintain glow plug temperature. When the engine starts, glow plug system is turned off. See Figure .