Why is the orange coil light flashing on your Nissan terrano dash board?

The orange coil light should come on when the ignition is turned to the first position - it lets you know power is going to the glow plugs to warm them. You shouldn't turn the engine over to "start" until the light goes out. I haven't seen / heard of a situation where the coil light "flashes", so apologies if I mis-interpreted your question.