How do i change glow plugs

If you are sure the glow plug relay and timer, which looks like a starter relay sitting on the intake manifold, are good. The glow plugs are located under the rocker arm covers between each injector. I would recommend purchasing new rocker cover gaskets, which incorporate the wiring harnesses for both glow plugs and injectors. They can be reused, but they will generally start to leak oil before long. The injectors are pretty easy to identify, they're the big square things with the electrical plug. the glow plugs have a single wire running to them. if I can recall they require a 10mm hex. hope this helps.

I have a 97 7.9 powerstroke can't find glowplugs please help never done before