modifying the circuit board
In order to get your new 08+ steering wheel cruise buttons to work properly, you will need to do some modification to the cruise switches circuit board. There are 4 resisters that need to be removed and 2 wires that will need to be soldered to the board itself.
In the pic below you will see 4 resisters that have been outlined and circled in red. These are the 4 resisters that you need to remove from the circuit board. You can heat them up with a soldering iron and they will come right off.
Once you have the resisters removed you will now be ready to solder on the 2 extra wires that you will need. the next pic has 2 red circles that show you where you need to solder each wire. Within those circles you will notice 2 solder points. You need to make sure you strip your new wire just long enough to span both points. This will help make for a better/stronger connection.
This pic shows the 2 new wires in their proper places. The red circle with the 2 black dots represent the solder location and the 2 solder points (notice how the wire is soldered to both points).
Please take note to the way the wires are running across the circuit board in the above pic. They need to lay exactly like this to avoid interfering with the buttons once you snap everything back together. You will notice that the rubber button cover for the circuit board will have to be trimmed slightly in order to allow the new wires to exit cleanly. Once you have done this, fish the new wires through the black tubing with the other wires. You can now snap your cruise switch back together.
here is the diagram. you have to put in diodes to separate the functions for the circuit board. this will allow the orange and white wire you just soldered in to have their own purpose in a sense. this is because the 08 only used one wire for 3 different functions.
On the Roll Connector, the spot to the left of where you plug in the green CC plug are not being used. this is where you will run wires down through the roll connector. You will need to run a wire down for the audio buttons, and if you choose a wire down for the illumination for the buttons. This is why I suggested just taking the pins out of the 08 connector in the beginning of this thread, because you can then use the pins to push them onto the prongs inside the roll connector (see photo below).
I suggest you remove the roll connector, as you have to pop open the bottom of the roll connector and solder in two wires onto the copper ribbon running through the roll connector. again, im an idiot and didnt take a pic of the ribbon. here is the picture explaining what you have to do, as well as the bottom roll shot of the roll connector.
After you have all the crazy wiring done for the cruise control, this is now the new layout to connect the 08 wheel to the 05 green plug for the CC.
08 Wires ------Green CC Plug
The green wire on your green CC plug, is now only used to connect to the airbag for the horn. Tape off or remove the end of the wire and only leave the connection for the tab on the airbag.
There are now two wires left over on the 08 wires. Black and Red. These are used for illuminating the buttons on the wheel. You will have to run the red wire down through the roll connector and to an illumination wire, and then ground the black wire. I connected it to the ORANGE wire on my Pioneer harness (its labeled illumination)
I grounded the black wire along with the BLUE wire for the audio buttons inside the wheel itself to one of the screws.