85 300 td wont start
 

My sons first car, 85 300 td bought it for 500.00 and only had to replace a few vacuum hoses and one fuel hose. He has been driving it for a year now with no problems. Now the engine wont shut off when the key is turned off, i rigged a vacuum pump and he can kill it in the cab now. The main problem is that two weeks ago the glow plug indicator failed to come on, he says he counts to ten and then starts the car. Now when you turn the key you get a little resistance but no starter activation. Battery is new and fully charged and all interior lights come on. Any help is greatly appreciated.