The 2500 is single stage. The 1500 have a dual stage. The plugs are different between the 2.
The climate control stuff is also different from manual to digital. Including parts like the blower motor and resistor.
I would suggest pulling all the trim panels off carefully from your donner and swapping all the wiring over from the roll over.
The dash is the most intimidating part if you have never done it before. Remove all the plastic trim from it first including the glove box along with the Cluster, the Radio, The climate control unit, and the passenger Airbag. 7mm and some #2 Philips screws for all the trim and a deep 10 mm socket for the back side of the air bag.
With the upper dash cover off, remove the 10mm bolt's along the windshield holding the stamped steel reinforcement braces. There is also a ground stud on each side in the corner. Pull the nut and remove the ground attachment points too.
Then move down to the Steering column. ***It is important not to move the wheel too much when you remove the entire column. You don't want to break the clock spring.***
There is a steel cover just below it that has to be removed to gain some access. It has 4 -10mm nuts holding it in place. Remove the Steering joint at the base of the column. It's like a 12 or 13mm I think. There is a lower Stamped steel brace that attaches to column brace and the floor that's like a 13mm head on it. Pull that stamped steel brace completely. While your at it there is a brace to the right of that that is a black tubular brace. It goes between the floor and the reinforcement for the dash. Pull that off too. Now you can disconnect the wiring connector for the steering column. There is a main connection point and I think 1 or 2 smaller connectors that have to be disconnected. Then you should be able to drop the 2 nuts holding the column to the big cast brace. I believe they are like a 16mm or 17mm. With the exception of the shift cable which I remember having to twist the column around to get it off, I believe you can start pulling the column out. If there is something else in the way, just slide it back up on the 2 studs and put the nuts back in place with a couple turns to hold it temporarily. The whole dash harness comes through the fire wall in a large round grommet to the fuse box. Separate this from the fuse block and push the gourmet inside the cab. I think there is also a wire harness going to the wiper motor that needs to also be un plugged and pushed back into the firewall.
At the right and left side of the dash there is some plugs for the Door harness and other things like the ac unit that will all need to be un plugged. I think there is 4 squarish connectors that will either be Black, Brown, White, or Green plugs.
I can't recall if anything else needs to be pulled or loosened before removing the dash assemble with all the wiring. But when you are ready, There is 2- 15mm headed bolts bolts that you can not see on the top side of the dash on the driver side behind where the cluster would mount. It goes through that casting into the fire wall area. You want to get those first so your not fighting it later. Then there is 2- 15mm headed bolts on the left side and 3- 15mm beaded bolts on the right side.
