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

TJDave

TJ Enthusiast
Supporting Member
Joined
Oct 27, 2015
Messages
125
Location
San Jose, CA, United States
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.
 

Jeep tj Finland

New Member
Joined
Dec 9, 2018
Messages
24
Location
Helsinki, Finland
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.
 

jgoberkeller

New Member
Joined
May 18, 2022
Messages
1
Location
Tucson AZ
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???
 

AndyG

TJ Guru
Lifetime Supporting Member
Joined
Jul 30, 2018
Messages
13,077
Location
Alabama
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.
 
  • Like
Reactions: TheBoogieman

pretex811

New Member
Joined
Nov 6, 2022
Messages
4
Location
76034
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.