To see a Dead Shielded Elite, you must play Halo: Combat Evolved, where there is a glitch that allows you to see an Elite's shield, even when it is dead.
To do this, start any level , and play through it as normal, until you reach an Elite. Do not attack him, instead, wait until you get behind him, then beat him in the back, so that he'll instantly die. Now that you've done that, shoot his corpse. It should flicker like the elite is alive. This works with all types of Elites. It doesn't work in Halo 2 or Halo 3