Glow Plug System: Description and Operation

Fig. 29 Quick Glow System electrical schematic:

The quick glow system has two main circuits to maintain the glow plug at a constant temperature and to shorten pre-start time. One circuit is used to quickly heat the glow plug by applying battery voltage to the glow plug. The other circuit is used to maintain glow plug temperature after the designed temperature is reached by reducing the voltage applied to the glow plug. The quick glow system will be in operation only when engine coolant temperatures are below 86°F.