AC heater control mods

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

I performed the mod to the heater controls that disables AC unless button is pressed, and I’m so happy about it. Now all that remains for a perfect HVAC in this car is to make it so that it has no fan “flow” mode like so many cars before it have had. For some reason American cars refuse to offer this option which is strange to me. The flow mode is superior because it’s speed sensitive, and quiet and efficient.

Would any electrical gurus know an elegant way to do this? I’d be willing to give up my fan HI mode if it means I can shift all fan modes up one, freeing up the lowest fan mode selection for flow mode/fan off.

WWDiesel · **Posted:** Sun May 24, 2020 2:01 am

If you place the center rotary Mode Selector Switch to the "Off" position, the blower fan motor does not run.

gollygeemister · **Posted:** Sun May 24, 2020 5:08 pm

Jett wrote:

Would any electrical gurus know an elegant way to do this? I’d be willing to give up my fan HI mode if it means I can shift all fan modes up one, freeing up the lowest fan mode selection for flow mode/fan off.

I did exactly that, because the vents close in position O.
Just tape over the contact for fan speed 4 and air will be pushed in depending on your speed, exactly as you say - something I also find missing in modern cars. Or tape over 3 if you want to keep 4. Shifting the others would be harder and not really worth it.

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

gollygeemister wrote:

Jett wrote:

Would any electrical gurus know an elegant way to do this? I’d be willing to give up my fan HI mode if it means I can shift all fan modes up one, freeing up the lowest fan mode selection for flow mode/fan off.

I did exactly that, because the vents close in position O.
Just tape over the contact for fan speed 4 and air will be pushed in depending on your speed, exactly as you say - something I also find missing in modern cars. Or tape over 3 if you want to keep 4. Shifting the others would be harder and not really worth it.

Perfect idea thanks!

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

WWDiesel wrote:

If you place the center rotary Mode Selector Switch to the "Off" position, the blower fan motor does not run.

I get the off position but it closes vents and locks up all flow. My preferred normal driving mode is to have position selector in def or Def/feet and zero fan power, just natural air “flow”. It used to be standard, then it was optional and now it’s rare. It’s part of the pacification effort by the aliens.

casm · **Joined:** Sun Jan 29, 2006 5:05 pm **Posts:** 694

Jett wrote:

I get the off position but it closes vents and locks up all flow. My preferred normal driving mode is to have position selector in def or Def/feet and zero fan power, just natural air “flow”. It used to be standard, then it was optional and now it’s rare. It’s part of the pacification effort by the aliens.

If it's any consolation, this drives me nuts as well. I'd much prefer having two fully-off positions - one for the fan, and one for the HVAC blend system. This would, in theory, allow for the fan to be off but have all of the vent / floor positions available for use at speed - or to completely shut off the entire system.

Personally, I blame the reptilians. The greys aren't getting a pass on this either, but the lizards are the real problem on this one

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

casm wrote:

Jett wrote:

I get the off position but it closes vents and locks up all flow. My preferred normal driving mode is to have position selector in def or Def/feet and zero fan power, just natural air “flow”. It used to be standard, then it was optional and now it’s rare. It’s part of the pacification effort by the aliens.

If it's any consolation, this drives me nuts as well. I'd much prefer having two fully-off positions - one for the fan, and one for the HVAC blend system. This would, in theory, allow for the fan to be off but have all of the vent / floor positions available for use at speed - or to completely shut off the entire system.

Personally, I blame the reptilians. The greys aren't getting a pass on this either, but the lizards are the real problem on this one

Of course that’s who I meant. Wait, you mean there are other aliens besides reptilians?!! Oh *&^^&*.

layback40 · **Posted:** Mon May 25, 2020 7:39 pm

What would happen if you installed a off/on switch just under & to the left of the fan knob? I once installed an aircon & the fan could be left off with it running, when the fan was turned on it used to spit ice flakes out the vent.

gollygeemister · **Posted:** Mon May 25, 2020 10:10 pm

Yes, I'm careful not to turn on the AC in "fan off" mode so I don't ice up the evaporator.

WWDiesel · **Posted:** Tue May 26, 2020 2:21 pm

I have a simple solution if you want everything to function normal and keep the blower motor off.
Simply pull Blower Motor Relay out located in the Power Distribution Block in front of the Battery under the hood.
or
You could pull the No. 24 fuse in the Fuse Panel Junction Block on the left side of the dash.
------Note:Fuse 24 feeds 12v control power to the blower motor relay, but keep in mind, it also feeds 12v control power to the fuel heater relay.
---------Some say the fuel heater is almost worthless so for summertime driving, it probably would not hurt to disable it?

or
locate the ground wire for the Blower Motor Relay (terminal No. 85) A Black wire 14 gauge according to the FSM WD.
Cut the wire and wire in a simple single pole on/off switch which you could mount on dash or anywhere to your liking.
The ground side control circuit would be very, very low amperage and disabling the blower motor relay would not affect anything else...

:SOMBRERO:

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

WWDiesel wrote:

:idea:

I have a simple solution if you want everything to function normal and keep the blower motor off.
Simply pull Blower Motor Relay out located in the Power Distribution Block in front of the Battery under the hood.
or
You could pull the No. 24 fuse in the Fuse Panel Junction Block on the left side of the dash.
------Note:Fuse 24 feeds 12v control power to the blower motor relay, but keep in mind, it also feeds 12v control power to the fuel heater relay.
---------Some say the fuel heater is almost worthless so for summertime driving, it probably would not hurt to disable it?

or
locate the ground wire for the Blower Motor Relay (terminal No. 85) A Black wire 14 gauge according to the FSM WD.
Cut the wire and wire in a simple single pole on/off switch which you could mount on dash or anywhere to your liking.
The ground side control circuit would be very, very low amperage and disabling the blower motor relay would not affect anything else...

:SOMBRERO:

You’re not getting it, this isn’t a desire I have for full time disable, I need a fan for sure. But I want to option to have fan off and still have flow over the selected mode. Haven’t you had a car that operated like this? It’s very important imo. Also, I realized I could add a switch but that would complicate use somewhat. What I really like is the solution provided above by gollygeemister where the highest setting fan mode is disabled and made to be off. This is much more elegant than pulling a fused a relay. The only improvement would be to rewire them so that it’s the first fan mode that is off, but I’m not sure if that’s possible. I’ll take a look and report back. The idea here being that setting 3 is plenty of fan for any time, and the highest fan mode is like tornado level and not really ever used at least not by me in all the cars I’ve ever driven which is probably 100 cars or more.
An analogy would be that they give us high and low fan, so it stands to reason that we don’t want hi or full off, we like having an adjustable force, and to me the fan off, flow mode is the missing low end of the force that they abandoned for reasons I don’t understand.
I super appreciate the idea though, thanks for that, and keep thinking for me, but that’s a two switch solution and the gollygeemister solution is one switch, so it gets the nod this time.

WWDiesel · **Posted:** Wed May 27, 2020 2:47 pm

Jett wrote:

You’re not getting it, this isn’t a desire I have for full time disable, I need a fan for sure. But I want to option to have fan off and still have flow over the selected mode. Haven’t you had a car that operated like this? It’s very important imo. Also, I realized I could add a switch but that would complicate use somewhat. What I really like is the solution provided above by gollygeemister where the highest setting fan mode is disabled and made to be off. This is much more elegant than pulling a fused a relay. The only improvement would be to rewire them so that it’s the first fan mode that is off, but I’m not sure if that’s possible. I’ll take a look and report back. The idea here being that setting 3 is plenty of fan for any time, and the highest fan mode is like tornado level and not really ever used at least not by me in all the cars I’ve ever driven which is probably 100 cars or more.

Yes I do "get" it! Was just trying to help you find a simple solution.
And, I live in the HOT sunny south and believe me the "High" setting is not even high enough on our hot humid days when temperatures get above 100 deg.s F and humidity is 90% or greater.
So I would never defeat the High speed setting on my vehicles.
You should be able to just modify the HVAC rotary switch to defeat a certain speed or disconnect the wire for just one speed???

mrhemi · **Joined:** Tue Dec 08, 2015 10:46 am **Posts:** 180

Give it some time. The blower motor resistor will fail in at least one position eventually. Then you will have a "no fan" position on the rotary switch. Ironically, just as this thread appeared, the resistor failed on one of my CRDs, but I prefer the fan on at all times so a new one in on the way.

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

SUCCESS! I tore it apart and did some testing. I ended up choosing the second highest mode to be the one I disable but I moved the wire positions so that it’s still on the last position, formerly full blast, that is now “flow”. I would’ve put it at the bottom of the dial but you can’t because the wire sizes for the lower modes are smaller and can’t be easily shuffled around in the connector like the two highest modes can. So now the knob starts at low, then goes to low/med, then hi then off. This is exactly what I wanted so thanks!

I’d post a pic but apparently you can’t post pics here? That’s a shame.

WWDiesel · **Posted:** Thu May 28, 2020 3:35 pm

Glad you figured it out.
You can post pictures, you just have to use a picture sharing service like PostImage or one of the others listed below.

_______________________________________
Click on the IMG button on the top of your post.
[img]>Place%20your%20picture%20image%20link%20here<[/img]

some of the image hosting sites that can help you upload and share photos:
Google Photos.
Imgur. ...
Dropbox. ...
TinyPic. ...
Use. ...
Flickr. ...
500px. ...
SmugMug.

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

WWDiesel wrote:

Glad you figured it out.
You can post pictures, you just have to use a picture sharing service like PostImage or one of the others listed below.

_______________________________________
Click on the IMG button on the top of your post.
[img]>Place%20your%20picture%20image%20link%20here<[/img]

some of the image hosting sites that can help you upload and share photos:
Google Photos.
Imgur. ...
Dropbox. ...
TinyPic. ...
Use. ...
Flickr. ...
500px. ...
SmugMug.

I see you didn’t mention photobucket which is telling, unless you just forgot but they are a huge service that changed the rules mid game and are responsible for murdering millions of valuable forum posts all over the world and this is what all these services do so I’m weary of them. History shows that the forums that have their own image hosting survive better in the long run with preserving content. So I don’t really do the image hosting service thing. I personally think it’s a pretty massive tragedy that all the photobucket data was made private.

WWDiesel · **Posted:** Thu May 28, 2020 10:05 pm

Jett wrote:

I see you didn’t mention photobucket which is telling, unless you just forgot but they are a huge service that changed the rules mid game and are responsible for murdering millions of valuable forum posts all over the world and this is what all these services do so I’m weary of them. History shows that the forums that have their own image hosting survive better in the long run with preserving content. So I don’t really do the image hosting service thing. I personally think it’s a pretty massive tragedy that all the photobucket data was made private.

I agree, photobucket changing their policy killed it for many of us. I have no use for photobucket and would never recommend it for anyone.
There is an extension you can download for chrome that allows you to still see any photobucket picture
Google: Photobucket Hotlink Fix https://chrome.google.com/webstore/deta ... aedg?hl=en

I have been using PostImage every since the the photobucket fasico and have so far been ok with it.
But I do agree, we are at the mercy of any photo shearing service when sharing anything other than simple text on LOSTJeeps.com
I don't blame LostJeeps though, as server space can get expensive $$$

Jett · **Joined:** Fri Apr 17, 2020 12:07 am **Posts:** 250

Very cool thanks for that. Not sure I’ll be able to figure that out but I’ll try.

WWDiesel · **Posted:** Fri May 29, 2020 4:05 pm

Jett wrote:

Very cool thanks for that. Not sure I’ll be able to figure that out but I’ll try.

It's not to hard, simply register or join one of the photo sharing services, then upload your photo(s) to them,
then copy and paste a "Hotlink for Forums" between the IMG brackets and your picture will show when you submit your post.

Example: [img]=LOCATION/"NAME%20OF%20PICTURE%20FILE"[/img]

AC heater control mods

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