Glow Plug System
WARNING: This page is about a different car, the 2005 Ford Pickup, 2005 Ford F550 Super Duty, 2005 Ford F450 Super Duty, and 2005 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
Refer to the ENGINE CONTROLS - INTRODUCTION -- 6.0L DIESEL (99P F450/550) article.