Upgrade '16 Denali to HDMI input from '17 models?

[UNICORNDAD]

Yes I can do that sometime this weekend! So you just need underside of each circuit board?


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[atlankford]

I feel like the reality of this is fleeting. It's starting to look like it's not possible. And even if it is......retaining the HD video signal sounds like a major rework.

 

[Bardog]

I feel like the reality of this is fleeting. It's starting to look like it's not possible. And even if it is......retaining the HD video signal sounds like a major rework.

Agreed... Just did a 2000 mi road trip with the kids and they had no issue with the Amazon Fire Stick plugged into my ‘16 Denali console via composite. Switching to HDMI isn’t going to magically enhance the resolution of the rear screens by a great factor, or even a small one.

 

[UNICORNDAD]

Yes I agree a converter will not give you any better solution. That’s what I use now. I purchased the 17/18 module that has a hdmi port. The only way to work is by bypassing the existing harness or buying a new one to send hdmi to the head unit. The system already supports blue ray, so the annoying part is that some where in the line or unit it is downgrading for the rca composit line and inputting into the blue ray switch.

Does anyone have any knowledge on what prongs carry what on the 2015/16 composit line?




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[tullywork]

I've got a '16 Yukon XL and was pretty disappointed it had the composit connectors too. I tried a few converters and while they worked, it was more complexity/hassle than I wanted. Then Roku recent released (probably about a year ago now) the Roku Express+ (https://amzn.to/2MvSCwD) and it works PERFECTLY right out of the box. I really only wanted something to play Amazon Video and Plex and the Roku does the job. I originally wanted something that I could load a bunch of movies on an SD card or USB stick, but the streaming and $20 unlimited wifi data plan has been more than sufficient for our road trips. If you loose cell signal the video gets choppy, but streams much better than I originally expected it would (guess it buffers a bit in the background) that it performs better than expected. Might be something to try!

 

[cmatt]

For those of you asking about the pin out of the 12 pin X82 connector on the 2015-2016 suvs, here it is.

Here’s the 2017+ X82 connector.

The 2017 uses pins 1, 3, 7, 9 & 10 from the 2015-2016 connector. Those circuits are the power, ground and headphone signals.


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[cmatt]

I’ve got the 2017+ X82 audio/video adapter installed and working with the exception of the HDMI port in my 2015 Yukon. I’m still testing to see if I can get it to work. Both USB ports work/charge. I’ll expand on things shortly.

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[Darren Trokhan]

Thanks Matt. That's helpful.

The HDMI seems trickier. The 2017+ AV unit looks like it has two USBs, but one of them is for the video signal. I'm not sure of the name of the DVD unit in the dash, but I think the video needs to plug into that. You posted some wiring diagrams earlier that showed a LVDS connection that goes to the X5 port on the DVD unit. Do the 2015 and 2016 DVD units have that port for plugging in the video connection?

I saw a picture of the DVD unit in a stereo removal video on Youtube. It looks like there are several of the USB connections on the back, but I'm not sure what they all do. And I'm not sure whether the picture is of a 2017+ DVD unit or an older one.

DPT

 

[cmatt]

Thanks Matt. That's helpful.

The HDMI seems trickier. The 2017+ AV unit looks like it has two USBs, but one of them is for the video signal. I'm not sure of the name of the DVD unit in the dash, but I think the video needs to plug into that. You posted some wiring diagrams earlier that showed a LVDS connection that goes to the X5 port on the DVD unit. Do the 2015 and 2016 DVD units have that port for plugging in the video connection?

I saw a picture of the DVD unit in a stereo removal video on Youtube. It looks like there are several of the USB connections on the back, but I'm not sure what they all do. And I'm not sure whether the picture is of a 2017+ DVD unit or an older one.
View attachment 209467

DPT

Yes, the dvds have the same ports. The blue LVDS usb cable is the key. It connects the AV unit, dvd, front screen and HMI together. Unfortunately, the schematics aren’t comprehensive in what they show. That additional usb plug is fed by the blue LVDS usb cable that splits off the dvd plug. I believe it also carries the HDMI signal.

I’ll get my thoughts together and write up what I’ve done so far and where I need some input and help.

 

[mfennema]

I may be way off base, but is this as "simple" as swapping the modules and the old harness for the new harness that you posted earlier @cmatt ?

 

[cmatt]

I may be way off base, but is this as "simple" as swapping the modules and the old harness for the new harness that you posted earlier @cmatt ?

Almost. There’s one more usb that needs to be swapped in the dash.


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[cmatt]

So I wanted to document my progress so far with this. It can be done physically. As of the writing of this post, I am still working on the HDMI functionality.

My vehicle is a 2015 Yukon SLT with RPO U42 which is the rear entertainment system with RCA A/V inputs.

To swap in the X82 audio/video adapter module with the additional usb and HDMI outlet from a 2017+ suv, it will require swapping a usb cable in the dash, adding a usb cable to the center console and using a different connector for the module.

To obtain the usb cables, I had to purchase a center console harness and a dash harness. If any of you can help source the individual cables, it would be a great help.

Center console usb cable - 33183241

Dash harness usb cable - 33308529

This is what the specific LVDS usb cable that needs to be swapped out looks like out of a 2017+ suv.

Notice the HMI bypass module. That was added on 2017+ as a safety feature. I believe it allows a backup reverse camera signal. However, we won’t need it for our purposes.

The other difference is the split off of the DVD player to the center console. 2015s-2016s don’t have that. It brings the LVDS signal to the center console. It then connects to a new usb cable in the center console that connects to the X82 A/V adapter in the rear of the center console.

In the 2015-2016, the blue LVDS usb cable goes from the HMI and connects to the back of the front screen here. You can see it’s a double usb. It travels to the DVD player and terminates there.

Rear of DVD player

On the 2017+, you can see the cable split off again from the dvd

I routed the 2017+ cable along the OE path and plugged everything in.

If you recall, I said we don’t need the HMI bypass module. The issue becomes the keyed end to the usb. The HMI module is looking for a blue usb plug, but we end up with a gray plug.

If you look at the keying, it’s very similar. I removed the areas preventing the gray plug from seating to the HMI with a knife.

After that it plugged in fine.

I then routed the center console usb cable.

The next task is the 6 pin connector (5 spots used). 2015-2016 has a 12 pin (only 10 spots used). Those additional 5 wires carry the RCA signal and are not needed with the 2017+ A/V adapter. The wires needed are for the power, ground and wireless headphone signal.

There are a couple ways to accomplish getting the proper wires connected. I am working on a pigtail. The issue is that @pgamboa nor I can’t find a mating 12 pin connector. So I’m left with plugging in the individual wires.

I think a better method for now is just removing the needed wires from the 12 pin and landing them in the 6 pin connector.

Remove the CPA on the 12 pin and use a micro flathead screwdriver to release the terminals.

Then remove the CPA from the 6 pin connector, land the terminals and reinstall the CPA.

So both USB ports work including charging.

For the HDMI, I believe the signal is carried along the newly installed blue LVDS usb cable. However, the system doesn’t know to look for it. It doesn’t show as an option in the media menu. So, is it the HMI, dvd or radio that needs to recognize it? Is it swapping out one of those components? Is it a programming thing that @GTPprix can add? I need a fresh set of eyes on this.


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[mfennema]

Can you layout what the original connections look like from the back if the '15 module and where they go?

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[cmatt]

Can you layout what the original connections look like from the back if the '15 module and where they go?

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You mean this?

On the 2015-2016, the usb at the module and in the console compartment come together in this double usb plug at the front of the center console and connect with the black usb cables in the dash harness. It connects to the black plugs on the dvd and HMI.

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[cmatt]

Some additional thoughts I had on the matter:
I’m thinking the circuit board in the A/V adapter at the back of the console is processing the HDMI signal and sending it down the blue LVDS usb cable that was added. From that direction, it enters the dvd first, then on to the front screen and HMI. The signal can also head out to the overhead screen from the dvd. I’m wondering if the DVD player needs to be from a 2017+. Thoughts?

 

[mfennema]

That could be a real possibility. I'm also wondering if there is something in the HMI that needs to be updated also??

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[Darren Trokhan]

cmatt,

Do you have any other relevant wiring diagrams that you haven't shared yet?

It seems like you have the wiring connected properly. It's just a matter now of getting everything to communicate properly. I wonder if there is some way to let the system know that an HDMI module is connected that doesn't require a firmware change.

The way the DVD and HDMI input modules are spliced together makes me think that you could switch to DVD mode and possibly see the output of your HDMI adapter. Although the system might kill power to the HDMI board when you are trying to watch a DVD.

Can you tell if you are actually getting power to the DVD module? Does the power go on and off as you switch between input modes for the display?

Also, where is the HMI module located? Is it easier to get to than the DVD player?



DPT

 

[cmatt]

cmatt,

Do you have any other relevant wiring diagrams that you haven't shared yet?

It seems like you have the wiring connected properly. It's just a matter now of getting everything to communicate properly. I wonder if there is some way to let the system know that an HDMI module is connected that doesn't require a firmware change.

The way the DVD and HDMI input modules are spliced together makes me think that you could switch to DVD mode and possibly see the output of your HDMI adapter. Although the system might kill power to the HDMI board when you are trying to watch a DVD.

Can you tell if you are actually getting power to the DVD module? Does the power go on and off as you switch between input modes for the display?

Also, where is the HMI module located? Is it easier to get to than the DVD player?



DPT

There aren’t any other wiring diagrams I’ve come across yet.

I think it is a programming thing with the HMI. Remember, my 2015 HMI is looking for the rca inputs. It doesn’t know the HDMI exists. I’m still troubleshooting it.

Yes, everything is getting power. I don’t believe it is switching on and off.

The HMI module is behind the glovebox and below the passenger airbag. You can get to it by removing the same cover that accesses the cabin filter.

 

[Jptri]

cmatt..
Have you had any revelations? I'm thinking it's a combination of a newer DVD player (84409491) and a newer HMI module (84331776 or 84546904) to make it work.

I have a slightly different problem. I have a 2018 with RSE (hdmi input). The input is not displaying any res higher than 480p. Signal from a Roku appears zoomed in to just the bottom left portion of what the Roku would normally put out. Yet, other 2018 Tahoes on the dealer lot display 720p just fine. I'm thinking the problem is either my version of the DVD player installed during the build (not support more than 480p from the hdmi input coming to it) or the HMI module. I have 84364936 which is an earlier build than the ones listed above. GM infotainment support is aware of the issue. GM tech support is telling the dealer techs that replacing the HMI won't fix the issue. Of course my response to them is "then what will make it output 720p... if you're so confident it's not in the HMI then where is the problem?". I haven't received that answer yet but will pass along if I find out.

 

[Seanjordan20]

Cmatt have you had any luck with figuring it out. I have a 15 Denali and have upgraded my HMI and DVD to the newer models. I am wanting to start the cabling for the module and don’t want to tear anything apart if it’s not going to work. Please let me know