my bkd has a rough start when cold and I think its my glow plugs

my glow plugs don't seem to be working there is no pre glow even tried unplugging the coolant temp sensor to see if I could get them to glow and they don't its just a no pre glow in vcds then after car is running I get post glow. seems like the plugs are not helping at the cold start.
is there anyway to change this in vcds? can I not set them to glow every start?