8.4" to 12.1" screen replacement

[kolian2012]

Hey guys i yave a 2024 ram 2500 tradesman with one zone climate and manual knob. did this swap and everything went great everything works other then hvac and Android auto says (pre production hardware not for resale)
I programed the body control module cabin net ics -no and cabin net dcsd yes and hvac controls are fully grayed out and nothing works other than rear defroster. If I program cabin ics to yes hvac is stuck at fan speed 4 and I can't adjust.
I tried factory reset of the head unit and nothing changes. Wondering what I am missing.

 

[alliss00]

I’m new to the forum and was looking for help with 8.4-12.1 swap. My situation is I have a 2024 Big Horn with a 12.1 screen. My son has a 2019 Big Horn with the non navigation 8.4. We’d like to swap them. The pickups are near identical so the trim would be fine. How much extra is needed to be purchased to make this possible since I could take whatever needed from each pickup. Thanks.

 

[kolian2012]

I’m new to the forum and was looking for help with 8.4-12.1 swap. My situation is I have a 2024 Big Horn with a 12.1 screen. My son has a 2019 Big Horn with the non navigation 8.4. We’d like to swap them. The pickups are near identical so the trim would be fine. How much extra is needed to be purchased to make this possible since I could take whatever needed from each pickup. Thanks.

You will need an hvac harness or re-pin the oem one and cut the tab on the original or pull all the pins from your bighorn and the male adaptor to fit the 12in screen and you will take the display wire and radio module from your bighorn With the 12 inch screen. Then you will need to program using alpha obd or similar.

 

[gustov_romanov]

Lol, sorry guys. I thought I was replying in the 5” to 8.4” thread. Like Brookelf said, you’ll have to install the cabin temp sensor and correct sun sensor to get close. Let me know if you need a plug n play temp sensor harness, I have a few made up. Your current sun sensor connector already has the correct wires for the ATC sun sensor.

Do you still sell this wiring harness? If not, where can I buy the connectors?

 

[kolian2012]

Hey wanting to install a sub to the 12 inch screen. Not sure where to post this but does anyone have the wiring digram from the back of the head unit to show which wires are positive and negative to what speakers? If wrong section to post this in i can delete.

 

[msnyder1112]

I did the 8.4 non nav to the 12 Uc5 and everything works great except for one minor thing.

I saw someone asked about it but no one ever acknowledged him.

My 8.4 non nav had the ability to zoom into the hitch on the backup cam. I don’t have that option now.
Anyone have any ideas?

 

[TheWaterman83]

I've read this a few times, but it seems to continuously evolve:

2019 Ram Rebel with 8.4" Uconnect 4, WITH NAV. I am being told if I find a 12" Uconnect 4, it's plug and play? No radio module needed?

 

[MannyN]

I've read this a few times, but it seems to continuously evolve:

2019 Ram Rebel with 8.4" Uconnect 4, WITH NAV. I am being told if I find a 12" Uconnect 4, it's plug and play? No radio module needed?

You need a new radio module to accommodate the big screen. You need to re pin the power connector and replace the LVDS cable. Then reprogram with AlfaOBD or J-Scan.

 

[Di54]

has anyone encountered a problem with touching the screen?, the screen does not respond to clicks and after some time starts working (maybe 10 minutes or maybe an hour), or maybe it starts working from the very beginning, everything is random, apparently some kind of software glitch

 

[msnyder1112]

has anyone encountered a problem with touching the screen?, the screen does not respond to clicks and after some time starts working (maybe 10 minutes or maybe an hour), or maybe it starts working from the very beginning, everything is random, apparently some kind of software glitch

Did you change your center stack option in Alfaobd?

 

[kolian2012]

Hi, had another question. Did this swap everything works but the temperature control is pretty much hot or on Low slightly cool max ac is not blowing very cold either. What could be the fix for this?

 

[msnyder1112]

Hi, had another question. Did this swap everything works but the temperature control is pretty much hot or on Low slightly cool max ac is not blowing very cold either. What could be the fix for this?

Did you change the setting to auto with alfaobd.

Mine acted strange like that… I added the auto temp sensor. Pretty easy to do and now it works great.

 

[kolian2012]

Did you change the setting to auto with alfaobd.

Mine acted strange like that… I added the auto temp sensor. Pretty easy to do and now it works great.

I ordered the sensor and it came in but I wanted to make sure that it wasn't something else. Before I splice into the wires. Thanks I will install that. Iset hvac in alpha obd to dual climate atc.

 

[msnyder1112]

I ordered the sensor and it came in but I wanted to make sure that it wasn't something else. Before I splice into the wires. Thanks I will install that. Iset hvac in alpha obd to dual climate atc.

Yeah. Adding that sensors made mine act normal.
It’s pretty easy. Just take your time.

 

[Infotainment]

I ordered the sensor and it came in but I wanted to make sure that it wasn't something else. Before I splice into the wires. Thanks I will install that. Iset hvac in alpha obd to dual climate atc.

If you don't want to splice into your wiring, we sell a wiring harness to allow you to install a cabin sensor and sun sensor into your vehicle with ease. We even have a upgraded harness coming in the next 2 months that will be plug and play on the HVAC module's two connectors to add cabin and or sun sensor.
19+ Rams have the same HVAC module as Wranglers and Gladiators, so this harness will work as well. Click here.
Alternative is to buy the harness for cabin sensor and posi tap into the correct lines. Click Here. Feel free to use our video to help with that even if you don't buy any harnesses.

 

[BigPapaXLI]

Hey all - so I'm in need of a bit of help. I have a 2021 Ram 1500 Laramie with the 8.4 non-nav UC4 from the factory. I picked up a 12" UC4 setup on eBay from a guy who pulled it from his 2020 1500 and swears it was working when removed.

Long story short, I have everything wired up (all harness cables from the truck and the LVDS cable from module to screen) and made the changes to ICS (not enabled) and DCSD (enabled) in AlfaOBD. I have double and triple-checked the wiring, even re-pinned the HVAC harness to be sure it wasn't a bad adapter. All the buttons on the surround work (A/C, hazards, etc) but I get nothing from the screen and no sound from the radio. Just black screen of doom.

I pulled fuses F41 and F44, tried pulling the negative terminal on the battery and left it for over an hour, power cycling the truck, and resetting the ECU in AlfaOBD to no avail. I'll list the parts below in case anyone knows something I don't. Dude swears it works, but I'm starting to think I need to submit a claim on this thing.

Module: 68378392AB
Screen: 68312620AG

I know the module is from a 2500, but from everything I've read in the forums folks swear it works in a 1500. If somebody knows different, let me know!

 

[MannyN]

Hey all - so I'm in need of a bit of help. I have a 2021 Ram 1500 Laramie with the 8.4 non-nav UC4 from the factory. I picked up a 12" UC4 setup on eBay from a guy who pulled it from his 2020 1500 and swears it was working when removed.

Long story short, I have everything wired up (all harness cables from the truck and the LVDS cable from module to screen) and made the changes to ICS (not enabled) and DCSD (enabled) in AlfaOBD. I have double and triple-checked the wiring, even re-pinned the HVAC harness to be sure it wasn't a bad adapter. All the buttons on the surround work (A/C, hazards, etc) but I get nothing from the screen and no sound from the radio. Just black screen of doom.

I pulled fuses F41 and F44, tried pulling the negative terminal on the battery and left it for over an hour, power cycling the truck, and resetting the ECU in AlfaOBD to no avail. I'll list the parts below in case anyone knows something I don't. Dude swears it works, but I'm starting to think I need to submit a claim on this thing.

Module: 68378392AB
Screen: 68312620AG

I know the module is from a 2500, but from everything I've read in the forums folks swear it works in a 1500. If somebody knows different, let me know!

Did you use the old LVDS cable from your module? If so, it will not work as you will need a different cable.

 

[BigPapaXLI]

Did you use the old LVDS cable from your module? If so, it will not work as you will need a different cable.

I used the one that came with the setup. Mine was non-nav and didn't have an LVDS cable with it.

 

[MannyN]

I used the one that came with the setup. Mine was non-nav and didn't have an LVDS cable with it.

Did you re-pin the plug or did you get a adapter harness? i did exactly the same swap 8.4 non nav to 12.1 uc4. Re-pined the plug, new LVDS cable, everything worked at the 1st try.

 

[BigPapaXLI]

Did you re-pin the plug or did you get a adapter harness? i did exactly the same swap 8.4 non nav to 12.1 uc4. Re-pined the plug, new LVDS cable, everything worked at the 1st try.

I actually did both. I have the adapter harness which is wired correctly, but just to double check it I re-pinned the harness on the truck itself. Same result, the buttons on the surround work fine, but the screen won't power on and the volume/tune knobs do nothing (no sound from radio at all).