On LB7 engines with federal emissions, the glow plugs are tied together with a bar that transmits the power to each plug. In harsh climates, its not uncommon for the bar to rust through and break the circuit, not allowing proper glow plug operation. Inspect the bar carefully and replace it if signs of corrosion are present.
Glow plugs are one of the most important components when trying to start a diesel in cold weather. Worn or in-op glow plugs can cause a hard start or even check engine lights on today's newer trucks. Comes with nutView full product details