The wire to feed the glow plugs will be corroded and needs to be made into a new clean connection ,mine was like this and failed to start even when warm but since I have done this its fine, The wire is located on the glow plug bar right at the back with a black screw on top a little tricky to get at so i took mine off that and put it on the front one for easier access and to keep an eye on it.
Derek.
February 2011