check the wire connecting all your glow-plugs for even the slightest of breaks.
To check glow plugs:  remove them and using a set of jump leads, clamp - to the thread of the plug and touch the bit on the bottom where the nut is/was with the +       The plug should glow red straight away,  if not replace it.
Also,  in cold/frosty mornings wait till the glow plug light on your dash goes out and after about 5 secs turn the engine (the plugs still heat for a while after your dash light goes out)
;-)  good luck!
                
 TamTheBam
                
 January 2005