My TDI glows great in the winter and will start after three glow plugs turns. Unfortunately in the summer it starts like a bag of crap. The glow plugs come on for a quick second. I normally let it glow 10 times before cranking, and then she cranks and struggles to start. Normally takes me 3 times of doing the glowing and letting it crank to warm up to start. Once it’s running, it drives like a dream. I am thinking maybe a sensor or relay is not functioning, but I have no clue where to start. Has anyone had this issue before?