Welcome to the forum, I'm surprised that you didn't get a response sooner, next time try being topic specific.
I know this isn't going to set well with the guys that go by the book, but it's a possible way for some guys without meter or other means of testing.
Disconnect the battery and connect the leads of your 10 amp battery charger to the battery cables. Place the charger in a place where you can see the meter of the charger while sitting in the drivers seat. Make sure that all electrical things are off. Turn the key to the position that will enregize the glow plugs and see what happens. It will clearly peg the meter on the charger. You won't know if all plugs are working but you'll at least know if the system is functioning.
Did you try a search on glow plugs yet? Im sure theres tons of info on the subject.
You didn't say what year your CD is. It will make a difference, I believe the models prior to 80 had a series glow plug circuit, and the 80's on, were parallel.
Also welcome to the informal CD club, I've had a 80 for about five years, and just bought a 83 a couple of weeks ago.