How to Add Automatic Temperature Control (ATC) to a Manual Temperature Control Truck

Ghost_RAM said:

While I did not research this, here is a link to GGGCorps page on rain/light sensors. There are also brackets for humidity sensors and I am pretty sure one of these will work if you want to go the OEM route for mounting the humidity sensor. The "GBR 1892" looks like the one. Their customer service is top notch if someone wanted to look into this further.

https://gggcorp.com/Rain-Light-Sensors.html

Since it wasn't as crucial on how the humidity sensor was mounted unlike the rain sensor, I opted just to double side adhesive the sensor and cover into place but who knows maybe I'll redo the humidity sensor at some point.

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I reached out to AutomotiveDesignGroup.com and they said the bracket was listed in their catalog as 'Chrysler 300' so it is very likely the bracket we need for the humidity sensor. They said they did not sell to consumers, so I am still looking for a way to purchase the GBR 1892 bracket. If I figure it out, I will post back.

sdwalter said:

I reached out to AutomotiveDesignGroup.com and they said the bracket was listed in their catalog as 'Chrysler 300' so it is very likely the bracket we need for the humidity sensor. They said they did not sell to consumers, so I am still looking for a way to purchase the GBR 1892 bracket. If I figure it out, I will post back.

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Interesting that they don’t sell to consumers. They’re the ones that sold me my lens kit and extra pads for the rain sensor. Let me see what I can come up with for the humidity sensor.


Edit 1/8: My contact at GGG has went silent. I've reached out to someone else in hopes they'll have an answer.

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Hi All, I've read thru the forum posts a couple of times, and I'd like to ask a couple of questions if I may:

I just purchased a 2015 1500 Tradesman.. (4,000Km's away at the moment so physical access to check things is rather difficult)

I really want to do this MTC to Single Zone Automatic Temperature control.

#1 - The HVAC Module required, would that module already be in the vehicle? Or do I need to get/ swap it for a different one?

#2 - I'm a bit confused about the bezel. In places I see that one of the members is modifying the circuit board for single zone. I have a bezel with dual zone controls in it from a donor Laramie wreck. Are there circuit board modifications required? Or can I just use the dual zone control as is? (obviously the passenger side would not function, I think).

#3 - You guys show a single zone ATC set of buttons. Where did you get those ? Part Number or vehicle/model that has them. If I were to get a set of single zone buttons, would any circuit board modifications still be required?

Thanks very much, great thread by the way. I'm really looking for to doing this mod, along with an 8.4 Nav upgrade and heated/cooled/power set upgrade with heated steering wheel (gets too cold for me here in Canada these days... I'm just gettin' older I guess.

GordDavey said:

Hi All, I've read thru the forum posts a couple of times, and I'd like to ask a couple of questions if I may:

I just purchased a 2015 1500 Tradesman.. (4,000Km's away at the moment so physical access to check things is rather difficult)

I really want to do this MTC to Single Zone Automatic Temperature control.

#1 - The HVAC Module required, would that module already be in the vehicle? Or do I need to get/ swap it for a different one?

#2 - I'm a bit confused about the bezel. In places I see that one of the members is modifying the circuit board for single zone. I have a bezel with dual zone controls in it from a donor Laramie wreck. Are there circuit board modifications required? Or can I just use the dual zone control as is? (obviously the passenger side would not function, I think).

#3 - You guys show a single zone ATC set of buttons. Where did you get those ? Part Number or vehicle/model that has them. If I were to get a set of single zone buttons, would any circuit board modifications still be required?

Thanks very much, great thread by the way. I'm really looking for to doing this mod, along with an 8.4 Nav upgrade and heated/cooled/power set upgrade with heated steering wheel (gets too cold for me here in Canada these days... I'm just gettin' older I guess.

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1. The module you use depends on the truck year. I believe there is a list of part numbers, based on Year....somewhere on here.

2./3. The Single Zone bezel for ATC is not an actual Mopar part, because ATC in single zone is not available in Ram trucks. There is a member on here that makes the harness for this mod and he will also modify the MTC bezel with ATC buttons to look and function as it should.

If you have a Tradesman, you probably have an RA1 or 2 radio, I THINK this mod has to be in conjunction with an RA3/RA4 radio swap. The radio swap is what actually requires the new HVAC module. Hope this helps. I’m sure someone will explain it more clearly.

@Mpgrimm2 can probably explain this much better, since he is the one that makes the harness and does the bezel modification.

I just finished my upgrade using the wire harnesses from mpgrimm2 and it was very simple. I used the advice of just putting the humidity sensor in the rear view mirror. Programmed using the AlfaOBD. Even noticed the dealer never added the navigation lines to my rear camera when I paid for that programming. ATC is working perfectly. The only thing I’m now noticing is that my outside temperature is stuck at 61 degrees. Not sure what I did. There’s so many options in the BCM programming I must have done something. I seem to recall looking at my outdoor temp sensor location or something like that but not changing anything. Any thoughts?


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jdomke1 said:

I just finished my upgrade using the wire harnesses from mpgrimm2 and it was very simple. I used the advice of just putting the humidity sensor in the rear view mirror. Programmed using the AlfaOBD. Even noticed the dealer never added the navigation lines to my rear camera when I paid for that programming. ATC is working perfectly. The only thing I’m now noticing is that my outside temperature is stuck at 61 degrees. Not sure what I did. There’s so many options in the BCM programming I must have done something. I seem to recall looking at my outdoor temp sensor location or something like that but not changing anything. Any thoughts?

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I believe I have seen this mentioned over in the AlfaOBD thread somewhere. I've only used it myself 2 or 3 times and it would probably be a good idea to post this over there to get more eyes on it. @Ghost_RAM probably knows what setting it is for the ambient temperature sensor location (my gut is the default is 'not set')

M² Mods.

Mpgrimm2 said:

I believe I have seen this mentioned over in the AlfaOBD thread somewhere. I've only used it myself 2 or 3 times and it would probably be a good idea to post this over there to get more eyes on it. @Ghost_RAM probably knows what setting it is for the ambient temperature sensor location (my gut is the default is 'not set')

M² Mods.

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Either way, props to you. Excellent workmanship and quality product. Well worth the expense.


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Hi I’ve added the ATC with harness from M2. My question is does the heat only blow from the defroster and feet when using Auto? And does anyone else seem to feel when using auto in cold weather once the truck reaches the desired temp or slightly above it starts blowing cold air from the upper vents.

Joe Gomez said:

Hi I’ve added the ATC with harness from M2. My question is does the heat only blow from the defroster and feet when using Auto? And does anyone else seem to feel when using auto in cold weather once the truck reaches the desired temp or slightly above it starts blowing cold air from the upper vents.

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Maybe... It is probably trying to regulate the temperature to whatever set-point is selected. Do you have the humidity sensor up near the mirror?
Every AUTO HVAC I've had will switch between heat and AC (hot-warm-cool) depending on where the temp is set, outside temp, inside temp and bright sun heating up the interior also has an affect on the AUTO performance. I have a similar setup to yours but my 3500 already has the humidity sensor and it seems to work the same as my other cars.

Joe Gomez said:

Hi I’ve added the ATC with harness from M2. My question is does the heat only blow from the defroster and feet when using Auto? And does anyone else seem to feel when using auto in cold weather once the truck reaches the desired temp or slightly above it starts blowing cold air from the upper vents.

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My ATC Mod seems to work the same way. When in auto it only blows heat from the defrost and feet. It will blow a/c from dash vents. The temp of the air being blown seems to depend on where I have the cabin temp set and what the actual cabin temp is. The ATC does a very good job of maintaining my selected cabin temp.

I do have the humidity sensor behind the plastic cover where the mirror is attached to the windshield if that makes sense. I just feel like in vehicles that come with this stock do a better job of regulating without fluctuating so much. Just wanted to see if this is how everyone else's ATC is working.

I would really like to add this option to my 2016 Bighorn ecodiesel but I am concerned that after my truck is reprogrammed because of the settlement I will have to do it all over again. Does anyone know if that would affect it?

Giddy said:

I would really like to add this option to my 2016 Bighorn ecodiesel but I am concerned that after my truck is reprogrammed because of the settlement I will have to do it all over again. Does anyone know if that would affect it?

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There have been a few guys that have taken their trucks in to have the recalls done and it hasn't affected the changes they have made because they're re calibrating in your PCM and the codes for the Auto Temp Control are stored in your BCM. If you were to take the truck in and have work done and it did delete the code when you have the alpha tool you can literally put the code back in in 5 minutes so it's really not that big of a deal as long as you have the tool.

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Ricks Ram said:

There have been a few guys that have taken their trucks in to have the recalls done and it hasn't affected the changes they have made because they're re calibrating in your PCM and the codes for the Auto Temp Control are stored in your BCM. If you were to take the truck in and have work done and it did delete the code when you have the alpha tool you can literally put the code back in in 5 minutes so it's really not that big of a deal as long as you have the tool.

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Thanks Ricks Ram!

Giddy said:

Thanks Ricks Ram!

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Remember in order for your ATC to function correctly when you install the code you will need to get the conversion harness from M2mods (vendor on the forum) and install the humidity sensor as well as the interior temperature sensor. I would also recommend just taking the truck in and getting all the recalls done before you even set the code so you don't have to worry about it getting removed. Some guys just put their trucks back to stock when they take them in to get recall work done and when they come back they just turn the codes back on again because it's so easy to do.

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Ricks Ram said:

Remember in order for your ATC to function correctly when you install the code you will need to get the conversion harness from M2mods (vendor on the forum) and install the humidity sensor as well as the interior temperature sensor. I would also recommend just taking the truck in and getting all the recalls done before you even set the code so you don't have to worry about it getting removed. Some guys just put their trucks back to stock when they take them in to get recall work done and when they come back they just turn the codes back on again because it's so easy to do.

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Thanks again, I like the manual to automatic controls M2mods does to the bezel also. I may have to get that done but I will probably wait until the settlement gets finalized.

Ghost_RAM said:

This is also the way mine functions. FYI, I enabled the humidity sensor to complete this in Alfa and so far I have noticed no difference.

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When you say you enabled the humidity sensor in Alpha, d you mean going from vehicle config 3, auto dual zone climate, then to single zone auto climate? Or is there an actual setting that needs to be changed for the humidity sensor to be activated? If so, could you point me in the direction of the needed change? (I didn't see anything on first page, so hopefully I didn't miss it)

loveracing1988 said:

Well that's a far drive... It seems like the app I have does give the option to enable it. I am really tempted to do this mod now. If m2 mods happened to offer just the harness from the cabin air temp sensor to the ac module and the humidity sensor to wherever it plugs into it would probably be a hit too since it's such a cheap mod.

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Found this on post 494. So we should be activating the humidity sensor as well? Somehow I missed that.

load97 said:

Found this on post 494. So we should be activating the humidity sensor as well? Somehow I missed that.

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Most people do not activate the humidity sensor because the truck seems to pick up on it regardless. I think I read a post some time back where one member activated it and it actually caused issues with this truck but I'm not sure. The whole reason we started installing the humidity sensor is because before that no matter what setting you put your truck on your A/C compressor always ran even if you just had it on manual control and vent. After we added the sensor the truck detected it and when you have the truck on manual controls you can turn the A/C on and off. No one had ever even noticed the issue before one of the members replaced his A/C compressor and realized it never shut off. We traced it back from their in figured out it was because we did not have the immunity sensors wired into the system.

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Thanks for quick response. I posted a question in the HVAC problem thread as well. Here's what I have going (read below).

I noticed the the last two mornings something odd going on. FYI it is around -5*F out last few mornings this occurs.

Before I shut the truck off for the night when I get home, I make sure the truck is in auto climate control set at 74*F. In the morning I remote start the truck (Drone Mobile). After it's running 10 min (when I get in the truck roughly as I'm getting ready for work prior 10 min), I notice the climate control shows it's heating the floor only. I put my hand up by the defrost and there's slight amount of residual air flow. That's about it. So the window starts to fog up a bit. I manually hit the combo defrost/floor blend and it does as it should, but now it's not in auto. This has happened both mornings to work and when leaving work with about same temps outside. I was wondering if there is a setting to change in Alpha OBD for what defaults to for winter or summer? I also wondered about putting my 2015 HVAC module back in? After installing the ATC harness on Wednesday I didn't notice this behavior, but It was pretty cold out lol when installing everything. Any suggestions?

FYI - On my 2019 Jeep Cherokee it's always is defrost or a blend of defrost/floor (forget which) when started when cold outside.