i have checked several components and it doesn't start
Have you got air in the fuel system? Did your fuel gel when it was cold? Did you check the air filter?
Your no start condition could be any of a number of things. First, I will assume it is cranking but not starting. If you are seeing any kind of white smoke while it cranks, you are getting fuel to the cylinders. So air in the system or low fuel should not be the problem. If you are cranking and getting NO SMOKE and NO START, you probably are not getting fuel. Check your fuel filters for clogs or gel. Other things to check: 1.Check your battery connections for corrosion. Also check each battery's voltage. You should have two batteries. If even one of them is low or has a bad cell, it can cause a failure to start. This is because glow plugs (thos things that heat the cylinders so the fuel can burn) us ALOT of voltage. If they don't get the full voltage, she probably wont start. If the battteries are good, you may have a bad glow plug relay or bad glow plugs. Finally, if all this fails find a OBDII scanner and check for codes. Perhaps you'll find your answer there.
Sounds like a starter short. Maybe check the 12v cables that run from the battery to the starter, make sure they are all clean, and there are no tears. If nothing, check your Alternator (should be replaced after 1,000,000 KM) Otherwise, I think you're going to need someone to replace the starter.
