Like I mentioned in my post #2 above.. 1 st take your ohm meter.. put it on "resistance" at a low range .. Put the black negative probe on the negative battery lug and the red probe (+) to the large lug towards the drivers side of the glow plug relay, with your ignition key off...(see my gallery pictures).. If the reading is around 8 or 9 ohms, your glow plugs are good.. If not, then you can go check the valve cover connector to check each individual glow plug.. using the GGIIcIIGG method that Dean gave you above in the two links.