This is a COPY AND PASTE from a different forum.
Just saw your posts about wanting to convert to rotary knobs on your Wrangler. I had bought a '98 Sahara new and like yourself, I did not like the slide controls either once I saw the rotary knobs. I converted mine over, but it was an involved process, but I enjoyed it once I got into it. First, you have to have a different heater/AC box assembly because when Jeep changed the controls in '99, they also changed the heater housing to accomodate a small electric motor that attaches to the lower housing. This is what controls the temperature from the dash controls versus the old style with the direct cable. I know, you are probably thinking that you can just get a different lower housing and attach to the upper housing. I thought the same, but those housings are expensive from the dealer,(about $134) so I went the junkyard route and paid $75 for a complete housing out of a 2000. You might try car-parts.com The years 1999 - 2001 will fit your jeep with no issue, but up until 2006 may work. When I got it, I took it completely apart and cleaned it with "simple green" and it looked great. If you go this route and have air condition, you must get one that has both heater and A/C, as there is a difference. I figured that since I had the thing apart, I would replace both the heater core and the evaporator. I also decided to replace the gaskets/seals on the outside of the unit. It may have been overkill, but I did not want to have to redo anything later on after reinstalling the thing. If you do this method of getting one from a junk yard, it allows you to scavenge the regulators, blower motor, and resistor and such from your old unit as they will work on the newer unit. Now the wiring harness that leads directly to your blower will not work either. You will need one from 99 -01, but chances are when you get your housing assembly, the blower motor/wiring harness will be with the unit. If not, they are on ebay. Let's see-what did I do next. Oh, yes I kept my eye on ebay for a instrument panel wiring harness from a '99' - '01. A new one is around $186 from the dealer I believe is what i was quoted. I got one on ebay for $35. It doesn't matter if it is from a hardtop or soft-top as I will explain. The difference bewteen the two as best as I could surmise was the incorporation of the rear defogger and wiper into the wiring harness. The one I got was from a softtop and I have a hardtop, but it worked out fine. If you get one from a junkyard,don't panic with all the twist and turns you see in the wiring loom. The only one you are interested in is the gray plug that has about 20 leads going into it. It sits behind your left speaker. If you take the speaker out, you will see this mass of wires coming to a junction. The gray connector should be the top one, if it is like me '98 and I bet it is. I got this thing and pulled out my factory service manual and compared the two. Believe it or not, the connections/wire lead-ins are the same. Before I got into really the wiring installation, I traced down what wires effected the heater/ac operation. On the gray harness I spoke of previously, only 2 leads need to be switched out. You will see a red/green tracer in one position and if I remember, a red/white tracer. The rest of the wires in your current harness can remain. What I did instead of replacing the entire wiring harness, I took the harness I got from ebay, completely stripped the tape/wrapping from the wires to be able to separate the leads for the heater/ac controls, etc. You will find the colors I spoke of earlier plus some black leads that are grounds, orange wire which is for lighting and a green lead. Once you get a harness, you will see what I am talking about. I looked at the leads coming from the plug-ins to the new heater controls and that is how i detemined what I needed to keep and chunk the rest. I took the wires I determined that were required and wound them in electricians tape, then tied them with tie wraps to my existing harness. Most of the wires coming from the new controls go to your heater blower motor, blend door actuator, and the heater relay. The only ones going to the left side of the Jeep that plug into the gray harness are the red/green, red/white and the green wire. The green wire plugs into a plug-in down by your left kick panel. As I said, I did not replace the wiring harness already in my Jeep and at the gray plug-in, I simply pulled out the 2 appropriate leads and inserted the 2 leads from my newer harness. As for the green wire, you will have to contort under the dash, find that plug and remove/replace the green wire. You will also have some ground wires with eyelets, but they are grounds and you should see where they attach to the side by right kick panel. It sounds difficult, but it is not, Very straightforward actually. The hardest part is removing the heater assembly. You have to have to have the a/c system evacutated, disconnect you heater hoses, then the five nuts on the engine side of the firewall. On the interior, you have to remove the dash which means removing the steering wheel. In order to not worry about the airbag, disconnect your negative battery cable and let it sit for about 15 minutes. I went the safe route and took the whole battery out. Don't want that thing exploding on me. I got my new dash controls off ebay. There were 2 **** on the back of it that are for alignment purposes I guess, dremmeled those bad boys off and widened the mounting holes to line up with my dash holes, worked perfectly.
I put everything back together, carried it back to the Jeep dealer for recharge and believe it or not, it works like a champ. I love it! Costs: I probably have $600 in it, but I replaced the heater core and evaporator. You may choose not to. My advice is to take your time and have patience. The overall job is not that hard other than getting the dash out. Parts list: Heater/AC housing assembly- used from junkyard- I do not know where you live, but I got mine from Jones Autp Parts in Paoli, Indiana 812-723-5766. If you use car-parts.com, you will see others. Jones ships you the entire unit that includes the blower and wiring harness that goes to the the blower motor. Be sure you specify a unit that has both ac/heater. Seals/Gaskets - 4874069AB,4874068,4874064 Instrument Panel Wiring Harness- used,may can get it from the same place you get the heater/ac assembly Dash Control Unit - EBay or Jeepsareus.com Heater Core/Evaporator - if you choose to get one, I got mine from the local Carquest auto parts store as they were cheaper than the dealer.