I just installed a Power sliding rear window in my Express. I.have the 8.4 now but my truck came with the 5.0 with the overhead console. There were no wires there for mine at all in the overhead console. I did have the two power wires routed up my drivers side C pillar. They are Red/Yellow= power ignition on and Black for ground. That is the only factory wiring I had to work with. This is where the factory power window switch is powered from. I was able to get a harness out of a wrecked truck so I traced the wires. I don't have any other factory wiring but this is still simple to install. You need three things plus the wire to connect it all.
1. Power Sliding window
2. Power slider switch
3. Factory repair connector for a cleaner install for rear window PN...05161926AA
This is a simple reverse polarity setup there are no modules are codes involved on your sliding widow switch you have 5 pins. If you look at the switch with the pins if you look at the back of the switch with it facing away from you they are as follows
1.Upper left= open
2.Middle top= Power
3.Upper right=Close
4.Lower left=Illumination
5.Middle=Empty slot
6.Lower Right=Ground
To install
1.Tap the power and ground unto yor drivers side C pillar wiring as described
2 Run a wire for slot 1 open and slot 3 close from the switch over to the passenger side C pillar and the atach it to the connector 05151926AA. This will then be connected to the window motor.
3. Connect the illumination wire #4 to a dash controlled light source. I am using the light that illuminates the console. I had Benny an AllMoparParts.com look everything up for me and the harness that would be needed just for the back to go to the power slider was about a thousand dollars. You need to pull the headliner down to run your wiring but the actual wiring in itself is simple to do. I have the window installed and tested and it works great. I am going to run the permanent wiring when the truck goes in for the recall since they need to pulll the headliner down anyway. I know the mechanic and he is going to only atach what he has to that holds the headliner up and I will finish it up when I get it back. Since your truck is an SLT you may already have more of the wiring in place. I recomend shooting Benny a P.M so he can run your Vin and see. If you did it would remove a few steps. But either way this us not hard to do. If you have the Or/Brn wire Brn/Or wire and the Light brn/Dkbrn wire going down your passenger side C pillar it woukd indicate you had more of the wiring already in place. These are a few pics of the install. I was gonna take more but we were in a hurry becsuse of the weather. I went to.the locsl ACE Hardware store and bought the harware to install the motor.