I bought the Mopar speed control unit (paddle type) for my '07 Pat from a Jeep dealer on Ebay. It arrived without instructions (gasp!), but they pointed me to Mopar.com, and they had the installation documents there.
The instructions say if the three, critical wires are already in the harness under the hood, you can pass Go and move to Step 24 (or Step 20, depending which version of the instructions you have). I did have those wires, so I was able to just disconnect the negative battery wire and go immediately inside the vehicle and do the scary part: remove the steering wheel and air bag, unmount the horn return and springs, replace the shroud and add the control paddle, replace a small wire bundle, and manage to put it all back together without extra parts, broken plastic doohickeys, or getting to see the air bag deploy at close quarters.
The things I noted were that the instructions showed the springs on the horn to be loose, and mine had clips keeping them on (this was a good thing), and that the star drive bolts and screws were 25s, not the 30s the instructions called for.
It took just over an hour, mostly because I was scared shirtless that I'd break, overlook, lose, or forget something.
Putting the steering wheel back on was a bit scary, because at first it didn't seem to want to go back (I could not imagine having to explain that to my wife and a tow truck operator on the same day). Fortunately, it found the spot and slid in. Do remember to mark how your steering wheel was lined up before you take it off. I did, but I still wondered if I'd have to adjust it after I closed up.
Tested the horn and took her out on the road. Everything on the Speed Control works, and the "cruise" light even comes on on the dash. Car still steers properly, and the air bag didn't pop in my face as I drove.
I do have an engine picture light now. I read in one of the forums that that happened to someone else too, and that it went away after a short while. As my engine is running, and sounds and acts normal, I'm hoping it's because the battery was detached, and that the engine picture light will go away for me, too. I have a gas 2.4, and no dealer Star Scan was involved, but the instructions indicated it might be for the diesel version.
Still rollin'...
