Glow Plug
The glow plug provides a heat source for combustion to improve cold engine starting and operation. The glow plugs are made of a resistive material that heats up when electricity flows through it. The glow plugs are duty cycle controlled by the glow plug control module (GPCM) and activated when modulated voltage is supplied. The metallic instant start glow plugs can operate up to 8 minutes (Transit). The ceramic instant start glow plugs can operate up to 20 minutes (all others). The GPCM may activate the glow plugs during an extended idle at cold ambient temperatures. The GPCM provides battery voltage for approximately 2 seconds to heat the glow plugs, then modulates the voltage to 7 volts to maintain temperature. For additional information on glow plug system operation, refer to POWERTRAIN CONTROL HARDWARE Glow Plug Control Module (GPCM) in this article.