Hey everyone,
I’m working on retrofitting OEM ventilated and massage seats into my 2022 CT4-V Blackwing (Global B) using factory donor parts.

After speaking with a dealership tech, I was told:

• My VIN controls feature enablement in the BCM

• Since my car didn’t come with vent/massage from the factory, the BCM won’t allow those features

• Even if I program vent-capable K40 modules to my VIN, the BCM may still block the function

• Using a donor VIN in the BCM could trigger theft deterrent / immobilizer issues

So I’m trying to figure out if there’s a clean way to enable these features without changing the BCM VIN, such as:

• BCM feature flag overrides

• Calibration edits

• Engineering-level SPS access

• Or any other known method

---

Looking for Help With:

1. Has anyone enabled vent or massage seats on a Global B car that didn’t come with them?

2. Any known way to modify BCM seat feature flags without a VIN swap?

3. Anyone reverse-engineered the GM LIN commands for vent/massage?

Appreciate any info — even if the answer is “aftermarket is the only safe route.”

I have a backup plan If OEM enablement truly isn’t possible. I’m prepared to:

• Bypass LIN entirely

• Run the two vent fans per seat via PWM

• Run the single massage pump per seat via PWM

• And directly control the bladder solenoids with a microcontroller

It’ll work electrically — I’m just hoping there’s a simpler OEM-style solution first.

Thanks!

Hi, do you have the necessary BCM files?

I do not

In Global A, it was as easy as changing the necessary calibrations, either by requesting a VCI code or by changing the calibrations via DPS. But in Global B?
I suppose the method of requesting a VCI code from the dealership will still be valid on the Global B platform, but I don't know for sure.

We haven't had Global B in Europe.

3 hours ago, Arbe_gtc said:

In Global A, it was as easy as changing the necessary calibrations, either by requesting a VCI code or by changing the calibrations via DPS. But in Global B?
I suppose the method of requesting a VCI code from the dealership will still be valid on the Global B platform, but I don't know for sure.

We haven't had Global B in Europe.

Hmm, im not sure how helpful my dealership will be. Im honestly pretty disappointed the hoops I need to go through to do anything on this platform. Got any good ideas how I can request this from them? I dont mind just walking into the service bay and asking the techs, but this seems like a bit of a process. Plus, who knows if GM will accommodate since the vehicle wasnt built with it originally.

On 12/3/2025 at 2:25 PM, blocked said:

Hi, do you have the necessary BCM files?

How can i retrieve the necessary BCM Files?

program by sps, input vin that have your desired calibration. the calibration files save on spscache

If it wasn't built with those seats GM will not allow the programming for you to put them in. Seats have a huge liability.

4 minutes ago, BLKATSG said:

If it wasn't built with those seats GM will not allow the programming for you to put them in. Seats have a huge liability.

So basically i'll need to do it myself? Do you know if this is even an option?

I don't know if this is currently possible with Global-B

1 minute ago, BLKATSG said:

I don't know if this is currently possible with Global-B

Thanks for the info. Cars at the dealership. Crossing my fingers for someone to have some holiday spirit over there lol

If i were to purchase an MDI2, could I theoretically do this myself?

Does anyone know what might stop me at that point?

Dealership was a bust (as expected)

Hmmm. Should i be able to add the RPO code using this: https://www.cameraloops.ru/files/file/254-xml-files-video-tutorial/

Global B it is not possible at this time, there is no known path to do this

1 hour ago, crakavelli said:

Global B it is not possible at this time, there is no known path to do this

Do i have any path to get the seats working like OEM?

Good news and bad news. I was able to get massage function wo.rking. It seems to be controlled by the module under the seat. Ventilation though, does not work. RPO limited as imagined... Global B is annoying indeed

If you have J2534, i can help.

7 minutes ago, blocked said:

If you have J2534, i can help.

I dont have a J2534, but i have the Bosch MDI2

Bosh MDI/MDI2 -perfect

1 minute ago, blocked said:

Bosh MDI/MDI2 -perfect

Please let me know. Im not sure if i can contact you due to website restrictions. You could also post instructions here for others to learn from. Looking forward to hearing from you

First we need right call files. Read bcm and send me logo

4 hours ago, blocked said:

First we need right call files. Read bcm and send me logo

Could you post what the process entails?

19 hours ago, blocked said:

First we need right call files. Read bcm and send me logo

Can you find me on cadillacvnet? Im unable to communicate with you. You'll find me as Emu1342

Looking forward to see updates on this -

I want to put base non V ct4 luxury package heated/cooled

tan seats into 2026 ct4V-BW.

I’ve heard it will work all except ventilation