This modification will invalidate any warranty that you may have on your xbox, if you have warranty left on your box i strongly suggest you do not attempt this or any other modification that requires opening the xbox 360 unless you are prepared to face the consequences.
Yes this does make the xbox 360 quite loud, the use of a potentiometer could allow for a variable fan speed but i didn't have one to hand at the time of doing this mod.
Step 1: Introduction
The writing below is the theory on why i did this mod... it is not necessary for you to read it.
My xbox 360 was getting extremely hot and causing my games to freeze and at one point even gave me the red ring of death, so I set about trying to find a way to keep it cooler after doing some looking and probing with my vault meter. After looking at the fans in the back of the xbox i noticed that theyre listed as 12v, but when i attached my volt meter to the fan pins they are only drawing a 5v current. This is because when the xbox is relatively cool the fans are kept slow to keep the xbox quiet, and as it heats up the fan speed should increase, however this doesnt always work properly so i set about finding a 12v source to power my fans, i settled on using the dvd rom drive power cable. Well thats the background covered now to set about opening the 360.
To start with we will need some tools:
Torx screwdriver size T-10
2 small flat blade screwdrivers
Wire strippers, or sharp knife
Step 2: Removing the Case
First start by removing the faceplate, this is fairly easy, with the xbox on its side, give the base end a firm tug and the faceplate should pop free, don't be scared of pulling to hard, these things are fairly robust.
Next step is to remove the bottom and top vent covers, to do this use one of the small flat bladed screw drivers, by looking into the holes on the side of the case you should see 3 plastic tabs by pushing against these you can free the vents from the case, there are 3 plastic tabs on each side.
The Top is slightly more tricky. the front tab's are set higher so can't be accessed through the ventilation holes in the side of the case. to unclip these look at picture 3 for guide on how to get to the tabs.
one of the tabs for the top vent is hidden behind one of the rubber feet as shown in picture 4.
Step 3: Removing the Case (continued)
this is where the two screw drivers come into place.
as you can see in picture 2 if you start at the end of the box with the power connector and push a screw driver into each of these holes, you should hear a distinct clicking noise when the clip is depressed.
once these two clips have come undone use one hand to hold this end of the xbox apart using a small amount of pressure to make a gap between the two halves of the box
now push one of your screwdrivers into the middle of the fan ventialtion section, there are two clips here which come apart with very little force.
now push slightly harder with your hand that is holding the box apart, and proceed to press in the final 5 clips above the video port of the xbox each of these should make a distinct clicking noise as you work your way to the opposite end of the box.
now you have the back spread far enough so that the clips won't go back together turn the box around and unclip the large clips on the front (picture 3).
and remove the base section of the xbox.
Congratulations you have just completed the hardest part of this mod.
now look at picture 4, place your screw driver inbetween the black part and the plastic and pry these apart it should come off with very little effort
Step 4: You've Nearly Got the Box Apart.
You should be left with what looks like picture 2, except mine has some lights and bits in it.
Carefully lift the dvd drive from the box and remove both the cables from the back of the box as shown in picture 3. then also remove the cables from the points where they are attached on the motherboard.
now i couldn't get any pictures of the next steps as my camera died so i will do my best to explain...
take the dvd-drive power connector, take the two wires that would connect to these two points on the motherboard and strip them half way down, it is important that the original connections remain intact so when stripping try not to break the cable.
from these bare pieces of wire attach a short length of wire to each then wrap the bare wire in insulation tape to prevent any shorts.
you should now have two pieces of wire coming from your dvd drive cable. these need to be attached to the fan inside the xbox, the fan wiring is like this.
red + brown need to be attached to +12v
blue and black need to be attached to Ground
picture 2 showsd how my wiring looked afterwards.
Step 6: Re-assembly.
reconnect the cables to the dvd-drive
replace top of the case, flip over and re-insert the six screws,
place on the bottom panel clipping it together at the front first then at the back
replace top and bottom vent covers.
replace face plate.
your 12v mod is now complete.
turn on your xbox and let it run cool.