Ok how about this....

For those of you who want to open your 2004+ headlamps, but are unsure of how to go about it for fear of breaking/screwing something up this is for you.

First: This is not the only way to open them; as XCUSM5 and myself each did it differently than what I'm about to describe... BUT, as far as a relatively 'easy' for the average DIY'er and (IMO) the only way to get a proper seal with the butyl afterwards this is the safest, and least destructive route.

TO OPEN FACELIFT HOUSINGS (the average DIY'er guide)

***This is only a guide. So please read it through BEFORE you begin.***

Dremel w/ cutting thin cutting discs OR a thin hot knife
Torx set
Flat Head Screwdriver(s)
Sharp Thin Blade
Roll of butyl
Some kind of structural adhesive

First step is to strip down the housing to make it easier to work.

1) Remove the weather stripping that runs along the top and down the side.
2) Using a flat screwdriver pry off the metal clips highlighted in orange in the pic below. There are some on the back side of the housing, not shown in the pic.
3) Remove the small torx screws that hold the lens; Highlighted by the orange box....there is also another on the back side (not shown in pic).
4) Ok, now this is where things get interesting....using a dremel or hot knife, cut along the edge of the housing (marked by the green arrows) all the way around. Its easiest to start with area in the bottom left corner of the pic below, and work your way around slowly. You only need to cut the top of the black bit that covers the sealant the lens was pushed into...DO NOT CUT TO DEEP! Once you get all the way around, make one cut perpendicular to the cut you just made (labelled by big green arrow) to split the lip piece. Just work your way around underneath it carefully with screwdrivers and the knife to cut the sealant, and you should be able to get it off in one piece.
***Pay attention to the corner by the side marker light (specifically around the screw holes)...you may need to go AROUND the screw holes, NOT behind them like I showed in the diagram!***
5) Here's the difficult part that may require an extra set of hands...you need to cut the sealant underneath the lens. So using a long thing blade you should be able to get a spot started, and work your way from there. Once you're able to get the blade underneath you're basically home free as far as opening them up.

Putting them back together
Once you do what ever it is you need to, before you seal them up you need to do a couple things first.

1) Make note of where the sealant was placed from the factory around the marker lamp area, as you need to put it in about the same place.
2) Remove ALL traces of the old sealant from both the housing (including the first piece we cut off) and the lens. The key here is we want a nice clean surface for the butyl to adhere to.
3) Running along the top face of the housing trim piece, you'll see 2 small gaps. Cover them with a piece of foil tape the width of the butyl. This is only as a precaution, to prevent the butyl from potentially 'drooping' on/into those spots (one of which sits over the projector).
4) Run a single length of butyl around the housing against the backing of the housing. (It may help to test fit the lens here to see what I mean). The goal is to create a bead that once warmed the edge of lens will push into, essentially creating a water tight seal all the way around. Try not to stretch or change the diameter or the butyl when placing it; we want a bead as uniform as possible.
5) Oven Time! Using some common sense here, we want the butyl soft, but not to run....in and around the 225-275F range for a couple mins should do'er. Again...be careful here, but dont pull it out too early! It needs to be soft enough so when it comes time top push the lens in, we get a nice seal. If You've never worked with this stuff before, it may be a good idea to put a test piece on some foil to get an feel for the temp and duration needed.
6) Once you have the lens on, before the butyl cools, press the lip piece we cut off back on. Key here is to do everything while the butyl is still sticky.
7) Once cool, use some plastic structural adhesive to fill in any gap left from the cut you made. You want something that will be hard/rigid when dry.
8) Re-attach clips/hardware.



Like I stated before, this isn't the only way to get them open....but as far as a method that can be done by the average person, and provide a leak-proof & worry free seal (for any climate) this is the way to go.

Hope this helps everyone!

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