Procedure:I have gotten a lot of comments on the blue LED's in my air vents, so I figured I should write up a how-to. This is very simple as long as you know how to crimp wires and drill holes. In less than 10 easy steps, you will be shining bright.
1) Insert a flathead screwdriver underneath the vent bezel, and gently pry upwards. I wrapped masking tape around the head of the screw driver so I wouldn't scratch my paint job on the vents.
2) When you look inside the vent from the back, you can see the valve flap that opens or closes the vent... it is kind of in the way, and since I don't open and close my vents too much, I remove it permanently, but pease note that this process CAN be reversed to put it back on. You have to turn the valve open, and squeeze the base of it, and it should be able to pull out now. Do the same on the top of it.
this will leave you with a nice open space to work in.
3) Next, you're going to want to mark a spot on the bottom of the vent that you want to drill your hole to mount the LED in. Since I won't be replacing the valve flap, I mounted mine right in the middle where it would normall by hit by the flap. If you plan on replacing the valve flap, mount more to one side, or put one LED on each side of the vent. I simply scratched an X where I was going to drill.
4) Now, use a 7/32 drill bit and drill a hole where you made your mark. Make sure it is clean of any debris or melted plastic once you're done so that the mounting brace sits flush.
5) Now, take the wires coming from the LED and slip them through the mounting brace and then through your hole from the inside of the vent, so that the wires hang out the bottom. Push the mounting brace into the hole until it sits flush inside the vent. Then, pull/push the LED into the mounting brace.
6) Since the finish in the vent is flat black, the LED won't reflect too brightly inside of it. To fix this lumination problem, I lined the top of the inside of the vent with some aluminum foil. Other people have suggested painting the inside of the vent with a bright paint, such as Chrome or Silver. Don't worry, it wont get hot enough in there to burn anything. Make sure that the foil doesn't get in the way of the motion of the grill, move it all around and make sure it doesn't hit anywhere, and make sure you secure it with some tape around the sides so it won't move around.
I always check my lights before I wire them up in the car on a 9 volt battery. Put the pos. wire to one side and neg. wire to the other side and the LED should light up. If not, then you have a faulty light.
7) Now, back to the car. Run two wires (pos. and neg.) from a switch up to each vent. All of the LED's will be fine on one switch powered by a 20amp fuse.
8) Crimp the wires from the switch onto the wires from the LED using the proper sized butt connectors (18 gauge).
9) Now all that is left is to push the vents back into place, and LIGHT EM UP! Flip the switch and enjoy your new and unique lighting effects. As you can see, it is a very subtle but effective mod that not a lot of people are doing. Next, I'll be putting some in my radio pocket! Stay tuned!