S550 sync 3 to sync 4

[MH702]

I found a SYNC 4 conversion kit on eBay (F150 APIM + screen + adapter harness), and I’m thinking about installing it on my 2020 Mustang GT (S550).”since I have 2020 no need to replace the ACM “
Only required for 2015 to 2019
What I found on ebay :
2021-2023 Ford F150 8'' to 12'' Sync4 NAV Touchscreen Upgrade Kit Plug & Play

“The harness seems to be the same one that another guy used to upgrade from SYNC 3 to SYNC 4.”


I don’t have the parts yet—just considering buying the full kit.

Before I do, I want real feedback from anyone who actually tried this:

- Has anyone here installed SYNC 4 (from F150) into an S550 Mustang?
- Does it actually work properly or just partially?
- With a full kit + harness, is it close to plug and play or still needs a lot of modification?
- What features worked for you:
- backup camera
- steering wheel controls
- climate control on screen
- Any major issues (errors, lag, missing features)?

FORScan side:
I’m planning to handle the programming myself later.
Idea is to copy/paste the As-Built data from my current SYNC 3 APIM and see if it carries over, then adjust anything if needed.

- Has anyone tried copying SYNC 3 As-Built into SYNC 4?
- Does it help at all or completely different structure?
- What modules actually needed changes (APIM only or BCM as well)?

From what I’m seeing, these kits claim “plug and play” and include everything (screen, APIM, harness), but I want real-world results before buying.

If you’ve done this swap, please share:
- what worked
- what didn’t
- parts used
- how much programming was required

Trying to decide if it’s worth it or not.

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[FMLAExpert]

Sync4 is built off entirely different backend architecture entirely. It won't talk to the Mustang.

 

[WolfMxbee]

I have but I did a full S650 interior Conversion, the biggest difference is the screens and the data shared between the cluster and center screen, just the apim alone will not allow you to use all the functions, sync 4 also has automatic ac and dual climate so took me lots of programming of trial and error through forscan and asbuilt decoding between sync 3 and 4 to figure what each code does cause one as built line like 704-02-01 could change like radio type while on a sync 4 could change like differential type (just a random line as a example, not accurate just for demonstrating)

 

[MH702]

Thank you for your reply.

I agree that SYNC 4 is built differently from SYNC 3.

However, when I saw someone successfully complete the upgrade, it was surprising. It appears that the process involves replacing the APIM and screen (along with the required harnesses),
followed by trial-and-error adjustments using FORScan.(this what I think)

2015-2023 Sync4

 

[WolfMxbee]

Thank you for your reply.

I agree that SYNC 4 is built differently from SYNC 3.

However, when I saw someone successfully complete the upgrade, it was surprising. It appears that the process involves replacing the APIM and screen (along with the required harnesses),
followed by trial-and-error adjustments using FORScan.(this what I think)

2015-2023 Sync4

Ahhh yea they have a direct plug and play kit but that company also gatekeeps there methods and parts used

 

[MH702]

I hope I could find out how can this be done with minimal cost possible

 

[MH702]

I forgot to mention that many people have done this on F-150 and fusion

 

[FMLAExpert]

Ahhh yea they have a direct plug and play kit but that company also gatekeeps there methods and parts used

Oh wow. That is interesting. A shame. 2600 for a full Sync3 to Sync4 upgrade. Thats jokes. Wireless CarPlay adapters are 50 bucks.

The only thing that could get me to switch is if a larger screen was offered so you could have the persistent Sync functions nestled under the CarPlay window, like how it is on the current Sync4 implementations.

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