I am looking at a 240d that won't start............I am a farmer and have been around diesel engines.......but not mercedes.........I need some direction........

figure I will start with glow plugs and relay...........where is relay located?

battery is low from them trying to start it.........I will jump it with big cables I use on Farm tractors........where is starter plan on tapping on it........

Anyone that can take a moment and give me some insite I would sure appreciate it..........as this is my first maybe Mercedes............

it is I believe either a 78 or 77 model

any help appreciated!
Thanks Scott

Going to look at it like 1030 Monday morning........