Lioness,The first thing to check is the glow plugs. Make sure that you have power on both sides of the 80amp glowplug fuse. If that is OK, disconnect the glowplug wire from the relay and use an ohm meter to check the glow plugs. If they are ALL OK, check the valve adjustment. Tight valves make cold weather starting almost impossible. In the cold weather I always turn the key to preglow and when the glowplug light goes out I turn the key off then back on to preglow and after the light goes out the second time I start the car. When it is real cold I sometimes preglow three times. You could have water in your fuel filters and when it freezes it will block the fuel supply. You may have low compression in the engine. Low compression will keep a cold engine from starting and will require major repair. I hope that your problem is a small one. Happy holidays. Jay
PS Some where in my files I have a procedture to check the glow plug circuit. I can e-mail it to you, or anyone else, if you let me know.