Read the owners manual on how the flow plug light works. It behaves differently for different model years. Generally, a flashing glow light indicates one or more burned out glow plugs. Have you tested your glow plugs? There are many ways to do it, from very easy (with a clamp on ammeter) to a lot of work (take them all out and glow each plug individually).

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked