Would that be different than the amber lamp on the dash?
YES, if you connect a lamp to one of the actual glow plug wires you will see what is actually happening at the glow plug, the wait light actually means nothing.
If working correctly you will see the light lit at the same time the wait light is lit, then when the wait light goes out you will see the glow plug receive pulses for another minuet or two this is called "afterglow"
Many times if you cycle the run switch incorrectly or your wait light just flashes and goes out you will still see the controller sending afterglow pulses to the glow plugs, even if relatively cold if you wait for 30 seconds or so of afterglow the plugs will be hot enough and the engine will start.
And of course if you see a steady glow plug light after the wait light goes out it is time to turn off the batteries as the controller is about to fry the plugs.
This would be the very first mod I would make to any HMMWV except my Duramax as I don't use glow plugs on direct injection diesels.