Don't the 79s have a shunt? I know nothing of B vans though.
I don't know either, that's the first time I've heard of a shunt!
there are 2 types of amp meters. I don't know when they changed. early types pass all the current through the amp meter. so if it is disconnected or burnt out, you get no power inside the vehicle. later ones, had what is know as the shunt style, which is basically a parellel path that still reads the amps used. it wasn't as volatile as the early ones.
