The face of the HU is held on by plastic tabs. Just push in on the tabs and pull out on the plastic. Work your way around the perimeter of the face. You should be able to see how it comes apart from there. There are 6 small hex head screws that need to be removed once the face is separated from the metal case. I don't have a precision socket driver set so I used a needle nose pliers and that seemed to work alright.
There will be a separate circuit board for the display. This board is just clipped on the the reflector bowl. You will see what I mean once you get in there. You must unclip this board from the larger board. Twist out the factory bulb and holder. This might require a pliers.
From there, solder in your LED and resistor. I also used a piece of small diameter solid wire to get a better position with the LED. See the above pictures.
Leave the red film in the factory position until you are satisfied with the position of the LED just as a precaution the protect the display.

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