That "timing indicator" is called the CPS (crank position sensor) or "CAMP" by Navistar. All Powerstroke owners out in desolate country should carry a spare CPS, a 10mm wrench and a screwdriver or such to pry it out.

When mine failed, it was at the local burger joint and the engine just shut down, cold.

One indication is that the engine spins over while trying to start, but the tach won't give any reading.

Another "benefit" brought to us by computers on engines: overwise perfectly usable engines that fail in the middle of nowhere.