How to change early style sliding HVAC knobs to later style turn knobs

TJDave

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Below I will give you detail on how to change your 97-98 sliding knobs to turn style for your heating and cooling. I will tell you what I did; other years might work, but I will only tell you what WILL work. I have a 97 Sport, 4.0L manual 5spd.

I decided to do this because I disliked the sliding style, and I had all sorts of trouble with my blend doors not working properly. I also wanted to replace my heater core and evaporator. With that being said I spent $200 on a salvage heater assembly, instrument cluster wiring harness, vaccum line harness, and the turn style switches (all from a 2000 Sport from a fellow member of Hoosier Wranglers, you may purchase these items from a salvage yard or ebay but expect to pay more - $250 - 300+). I obviously purchased the heater assembly with the A/C options (not all assemblies have A/C). Also try to get the vacuum line harness that attaches the heater assembly to the HVAC control panel.

If you purchase a heater assembly from a salvage yard, this is the best, as it should still have the wiring harness, vacumm harness, vacuum actuators, and blower motor still attached. If it does not, I would pass on buying.

I spent $80 on a new heater core and evaporator (from RockAuto.com), and $55 on new heater assembly seals from Morris4x4 (pretty much the only place that sells the heater assembly seals for the 2000).

First, remove your dash and heater assembly. Here is a great step by step video. Helpful tip: plug the tubes coming from the heater box before removing.


After you remove your heater assembly you may replace your heater core and evaporator if you choose. I also replaced the seals on the heater assembly; outlined in red in the picture attached. After you are happy with your salvage heater assembly, and as long as you have all the items attached (mentioned earlier), you may install the salvage heater assembly into your TJ.

Now for the fun part. Take you dash and put it face down. You will be splicing wires into this harness. It is easier if you remove the harness from the dash, but you can try keeping it attached if you'd like. It is simple to remove (tip: you'll have to remove the speaker covers to unhook the grounds) But first go grab your new harness. Take the new harness and strip off all of the wrapping down to the insulated wires from the clips that attach to the HVAC controls to the BUS (the three large connectors grey, red, and green). You only need to unwrap to the grey bus. Also there will be a large grey connector that only has four wires connected (attached below) which you will need to unwrap as well.

You might be thinking, screw this, I'll just use the new wiring harness since all the connectors are all pretty much the same. I thought that too, but when I plugged everything in, it turns out the headlight switch changed from 97 to 2000. My fog lights were always on, my fog light switch controlled my dome light, and my headlights never turned on. Now it is possible you can just replace the wiring harness and avoid all of this, if you have a 98 and swap in a 99 harness, but I confirm it works. I know the 00 is not compatible as a complete replacement for the 97.

When I say splice, you can also put the wires into the pin if you know how to remove the pins without damaging anything. I don't have the tools, and didn't want to take the chance of damaging a terminal.

With your harness now unwrapped, you are only interested in the three terminals that plug into the HVAC controls and the one that plugs into the heater assembly (neon green terminal on the 2000, black on the 97). You will most likely have to cut, untangle, and re-attach a few wires to be able to separate the terminals you want from the rest of the harness.

Now during the course of splicing the wires to come, you also might have to cut a few ground wires (black or black with white tracer). Simply splice these into the ground wires that lead to the "eye" connectors on the same new/salvage harness.

There are only two wires that run from the grey bus to the terminal that connects to the heater assembly. They are both red, one with a blue tracer, and one with a green tracer. Cut those wires as close as possible to the grey bus.Now splice these wires into the grey bus on your stock wiring harness, just match up the color and tracer color.

The large grey terminal with only four wires, I mentioned earlier; cut the light green wire from that as close as you can to the terminal. You will need to splice this light green wire into the light green wire on the stock wiring harness clip (Large black clip with five pins that plugs into hvac controls; will be the only one with a light green wire).

Now there is an orange wire on a HVAC control terminal (black, small, five pin, flat). This wire leads to a junction of other orange wires and only comes out as one or two, so cut the wire before the junction. Splice this wire into the stock wiring harness clip (black, small, only has two wires; orange and black.)

Now that all of your wires are spliced in, go ahead and bundle the wires nicely and secure with electrical tape. You can also tape them to the harness. I did not cut off my old hvac control terminals, because I did not want to cap off a ton of wires.

Now take your HVAC control panel, you will need to widen or drill new holes to screw into the dash. On the back side of the panel you will also need to remove the plastic prongs as they is no hole for them on your dash (at least not on the 97)

Next you can go put your dash back on (heater assembly first, if you have not already). Make sure you plug everything back in. Re-attach your battery, as it should have been disconnected per the video to not set off an airbag. Make sure all lights work and your controls should all work now as well.

Recharge your AC, add coolant if need be, and everything should now work. Enjoy your new HVAC controls.
 
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Oh boy, will stick with my sliding knobs...unless someone who enjoys and knows what they are doing come to Finland and spend a day doing the job...wish it was a simple Plug&Play...but guess not.

I had to change the stereo (had a cassette player) and there was a simple adapter to the wiring and all worked smoothly. This heating change is too complicated for my experience and expertise.
 
I am going to resurrect this post.

I just updated my 97 TJ per the directions TJ Dave posted above. Unless I misunderstood something, I followed them exactly. I spliced the new heater harness into my existing dash harness.

Now the problem is that I have somehow hard wired my dome light to an always-on circuit. I closed the doors, I pulled the fuse, I played with the headlight switch. The only thing that turns it off is unplugging the sound bar wiring harness at the main wiring block on the left side under the steering column.

The only wires I touched: red/blue tracer, red/green tracer, orange, light green.

What the heck did I screw up???
 
I am going to resurrect this post.

I just updated my 97 TJ per the directions TJ Dave posted above. Unless I misunderstood something, I followed them exactly. I spliced the new heater harness into my existing dash harness.

Now the problem is that I have somehow hard wired my dome light to an always-on circuit. I closed the doors, I pulled the fuse, I played with the headlight switch. The only thing that turns it off is unplugging the sound bar wiring harness at the main wiring block on the left side under the steering column.

The only wires I touched: red/blue tracer, red/green tracer, orange, light green.

What the heck did I screw up???
@Jamison C Runs the electrical division-he will likely know.
 
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Below I will give you detail on how to change your 97-98 sliding knobs to turn style for your heating and cooling. I will tell you what I did; other years might work, but I will only tell you what WILL work. I have a 97 Sport, 4.0L manual 5spd.

I decided to do this because I disliked the sliding style, and I had all sorts of trouble with my blend doors not working properly. I also wanted to replace my heater core and evaporator. With that being said I spent $200 on a salvage heater assembly, instrument cluster wiring harness, vaccum line harness, and the turn style switches (all from a 2000 Sport from a fellow member of Hoosier Wranglers, you may purchase these items from a salvage yard or ebay but expect to pay more - $250 - 300+). I obviously purchased the heater assembly with the A/C options (not all assemblies have A/C). Also try to get the vacuum line harness that attaches the heater assembly to the HVAC control panel.

If you purchase a heater assembly from a salvage yard, this is the best, as it should still have the wiring harness, vacumm harness, vacuum actuators, and blower motor still attached. If it does not, I would pass on buying.

I spent $80 on a new heater core and evaporator (from RockAuto.com), and $55 on new heater assembly seals from Morris4x4 (pretty much the only place that sells the heater assembly seals for the 2000).

First, remove your dash and heater assembly. Here is a great step by step video. Helpful tip: plug the tubes coming from the heater box before removing.


After you remove your heater assembly you may replace your heater core and evaporator if you choose. I also replaced the seals on the heater assembly; outlined in red in the picture attached. After you are happy with your salvage heater assembly, and as long as you have all the items attached (mentioned earlier), you may install the salvage heater assembly into your TJ.

Now for the fun part. Take you dash and put it face down. You will be splicing wires into this harness. It is easier if you remove the harness from the dash, but you can try keeping it attached if you'd like. It is simple to remove (tip: you'll have to remove the speaker covers to unhook the grounds) But first go grab your new harness. Take the new harness and strip off all of the wrapping down to the insulated wires from the clips that attach to the HVAC controls to the BUS (the three large connectors grey, red, and green). You only need to unwrap to the grey bus. Also there will be a large grey connector that only has four wires connected (attached below) which you will need to unwrap as well.

You might be thinking, screw this, I'll just use the new wiring harness since all the connectors are all pretty much the same. I thought that too, but when I plugged everything in, it turns out the headlight switch changed from 97 to 2000. My fog lights were always on, my fog light switch controlled my dome light, and my headlights never turned on. Now it is possible you can just replace the wiring harness and avoid all of this, if you have a 98 and swap in a 99 harness, but I confirm it works. I know the 00 is not compatible as a complete replacement for the 97.

When I say splice, you can also put the wires into the pin if you know how to remove the pins without damaging anything. I don't have the tools, and didn't want to take the chance of damaging a terminal.

With your harness now unwrapped, you are only interested in the three terminals that plug into the HVAC controls and the one that plugs into the heater assembly (neon green terminal on the 2000, black on the 97). You will most likely have to cut, untangle, and re-attach a few wires to be able to separate the terminals you want from the rest of the harness.

Now during the course of splicing the wires to come, you also might have to cut a few ground wires (black or black with white tracer). Simply splice these into the ground wires that lead to the "eye" connectors on the same new/salvage harness.

There are only two wires that run from the grey bus to the terminal that connects to the heater assembly. They are both red, one with a blue tracer, and one with a green tracer. Cut those wires as close as possible to the grey bus.Now splice these wires into the grey bus on your stock wiring harness, just match up the color and tracer color.

The large grey terminal with only four wires, I mentioned earlier; cut the light green wire from that as close as you can to the terminal. You will need to splice this light green wire into the light green wire on the stock wiring harness clip (Large black clip with five pins that plugs into hvac controls; will be the only one with a light green wire).

Now there is an orange wire on a HVAC control terminal (black, small, five pin, flat). This wire leads to a junction of other orange wires and only comes out as one or two, so cut the wire before the junction. Splice this wire into the stock wiring harness clip (black, small, only has two wires; orange and black.)

Now that all of your wires are spliced in, go ahead and bundle the wires nicely and secure with electrical tape. You can also tape them to the harness. I did not cut off my old hvac control terminals, because I did not want to cap off a ton of wires.

Now take your HVAC control panel, you will need to widen or drill new holes to screw into the dash. On the back side of the panel you will also need to remove the plastic prongs as they is no hole for them on your dash (at least not on the 97)

Next you can go put your dash back on (heater assembly first, if you have not already). Make sure you plug everything back in. Re-attach your battery, as it should have been disconnected per the video to not set off an airbag. Make sure all lights work and your controls should all work now as well.

Recharge your AC, add coolant if need be, and everything should now work. Enjoy your new HVAC controls.

I know this is an old post, but in your write up, you mentioned large grey with 4 connectors attached below. Do you have pictures that didn't attach to this post? Thanks in advance.
 
I am aware this is an old thread but that only means the parts are even harder to find today. SO, is it possible to simply use a 99 and up HVAC control on the 97-98 TJs? YES I get the plugs are different,,,, Both HVAC controls have a multi position switch to control the blower motor and a multi function vacuum switch to control the blend doors. Assuming the panels will bolt into the older dash, one would think tracing the vacuum diagrams, transferring it over to the "new style" twist control, changing the old vac plug out to a new type or making an adapter along with a new style blower switch connector would be a doable deal... Another thing I noticed after watching the video on how to R&R a heater core. My 99 HVAC unit (under dash)does not look like that 02. I mention this for conversion purposes. A 99 HVAC control might be the better choice over the "02" as the 99 might be closer control wise to the 97-98. I have not compared a 97-98 HVAC control panel to a newer 99 up so it is possible that I am crazy and this is not a reasonable conversion for instance maybe the 97-98 uses vacuum and cable control, then your kinda out of luck LOL.
 
Thanks for the reply. I actually just finished the conversion. It was not that difficult to convert, just making sure you have all the right parts when you start. Works perfectly and looks factory when completed.
 
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Thanks for the reply. I actually just finished the conversion. It was not that difficult to convert, just making sure you have all the right parts when you start. Works perfectly and looks factory when completed.

As a 1997 owner, this caught my attention… Can you share a bit about what was necessary for the conversion and any surprises along the way?
 
I will summarize:
You will have to tear the entire dash apart, since wiring and heater box will need to be accessed. You need to find a 2000 to about 2002 (don't know if other years will work) ac/heater box. Biggest difference in what you have and the newer one, the "blend door" is activated with an electric actuator, not the cable you have on 97-98 Jeeps. You need an "instrument wiring harness" from the 2000-2002 Jeep Wrangler as well. You can find brand new heater/ac controls on Amazon and Ebay pretty cheap new. The vacuum harness from the new controls vs. the old controls are virtually the same, so no issue there. You will have to remove your old heater box entirely, install the newer year box. From there, you will be using just the connectors/wires in the new harness for the controls, and removing and replacing 2 wires on the gray connector to the left of the steering column, and tapping into the old harness the light green and orange wire. I don't have it written up, but you can text me at 682-429-3139 and I can fill in some of the details. In the end, not that hard, just have to double check everything as you go.
 
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