by: Mean Green
Nov. 13, 2011
In the following article, I shall explain the steps to complete a LED retro-fit into the Map Lights in the overhead consoles of the GMT400's.
-Flat Screw Driver
-Dremel Tool (Or round file)
Skill Level: Moderate
#194 (T10) LED's of your choice. A 9 SMD LED bulb is the largest bulb that will fit into the housing (Length AND width wise). I used a White 9 SMD (3 Cell per SMD) for this, and worked out great!
Time Required: Approximately 1 hour
Step 1: To begin with, you’re going to have to remove the reflector/bulb holder assy. If you look at the center of the lens, you will notice a Torx style shape in the lens. Take a flat screw driver and gently insert it into these grooves, turn the assy counter-clockwise and it will release from the console. Be careful to catch it and not let it fall to the floor!
(after removing the assy. from the overhead console)
(Stock photo of the style of LED I used)
Step 2: You will now see the bulb holder at the top of the assy. It is black in color and had 2 copper colored contacts on the top of it. It is held into the top of the housing by 2 plastic clips that are released by pressing them in with a small screwdriver. After you have the bulb holder out of the light housing you are ready to proceed to step #3!
Step 3: Start off by placing the new LED bulb into the bulb holder, and test fit it into the housing to see how much you’re going to need to clearance the housing (this will vary due to different style bulbs). The hole inside the housing is round, the style of LED I used is square.
(Picture of the part you’re going to make square)
Step 4: Using your Dremel tool or a round file, start taking material off the sides off the holder (The narrow part that goes from the main reflector to the piece that houses the bulb holder). You’re going to have to take a good amount of material off of this are in order for the LED to fit. Take little by little to ensure you don't take too much off. Then flip the housing on end (how it sits in the console) and make the round hole inside the housing square. Make it as large as possible without corrupting the integrity of the housing. The LED I used sits about 1mm above the lens when fully installed.
Step 5: With your dremel, go to the very top leading edge of the reflector housing and clearance it a bit to allow room for the square LED to fit into the reflector. Keep test fitting until the LED slides into the housing without any force.
Step 6: Blow out all the filings with compressed air or other means. Just make sure to get all the stuff out of there so it doesn't sit on top the lens and affect the light output.
Step 7: Install new LED bulb into the housing and re-install the housing back into the overhead console by doing step 1 in reverse. Now repeat for the other map light!
(Picture showing the difference in intensity, color and light output between the original style bulb vs. the new WHITE LED Bulb on the right)
(Picture of both map lights converted to 9 SMD WHITE LED's)
(Photo of light output. NOTE: a 12 SMD LED is also installed in the dome lamp)
I hope this helps anybody that is looking to do this out! It was a VERY worthwhile upgrade to do, as the light output is FAR superior of that of what it replaced! And the color is also a very eye pleasing upgrade as it appears much more intense and cleaner looking!