[Android Auto General] retracnaes:
For my fellow GMC Sierra owners having problems @xdcowboysx @random9848 @charlie.busher @allmusicmyne and potentially other similiar GM vechicle owners (maybe more) I have something for you to try. I spent about 6 hours f'ing with this thing wanting to get it to work. I originally had one instance of it working early, but then failed consistently, so that told me it was possible. I believe it's the way the headunits in the Sierra's negotiate the connection. Here's what I would offer you to try and hopefully have success getting this going. Keep in mind that I didn't enable signal strength monitor, or turn off signal scanning, clear data/cache of google play services, or any other similar ideas throughout this thread.

Vehicle: 2020 Sierra with IOS radio system (8"/no factory nav)

Phone: Samsung Galaxy Note 20 Ultra 5G (not rooted, latest firmware)

AA Wireless: 1.80 firmware

*AA Wireless*

- Plug in the AA Wireless module into a power source (not your truck)

- Configure the device to all default settings, including Default for USB mode

- Reset AA Wireless by pushing reset button for 5-7 seconds

- Remove AA Wireless from power

*Phone*

- Unpair phone from AA Wireless bluetooth connections

- Unpair/remove truck bluetooth connection

- Go into Android Auto settings

-- Remove all vehicles from Android Auto settings

- Turn off USB Debugging (if enabled in phone developer settings)

- Go into App settings

-- Clear cache and data from Android Auto

- Go back into Android Auto settings

-- Set "Start Android Auto automatically" to "Always"

-- Set "Wireless Android Auto" to "On"

- Enable Developer Mode

-- Enable "Add wireless projection to settings"

- Disconnect any active bluetooth connection such as a watch, headphones, etc (you don't have to unpair, just kill any active connection) Just go into bluetooth devices and tap it to disconnect

*Truck*

- Start your truck (not just accessory)

- Unpair phone completely from truck through the dash

- Plug your *phone* into the truck and go through the Android Auto setup

-- Ensure you have Android Auto running on the dash

-- NOTE: This will reestablish the bluetooth connection with the truck, you should not do it manually. You will get the prompts for the truck to access your messages and contacts, I approved both in this process.

- Unplug your phone

- Plug in your AA wireless device using a USB-C to USB-C cable to the *dash* port NOT the center console port

-- NOTE: The USB-C to USB-C cable that came with my Note 20 Ultra was the *only* one that worked out of 8, this is critical to keep in mind

- Establish bluetooth pair between phone and AA Wireless device

-- Wait for solid blue light on AA Wireless device indicating good connection to phone

- Go into AA Wireless app and turn "Passthrough" to "On"

At this point my device started working after the next subsequent reboot, and I made sure everything was operational. At this point I held my breath and unplugged it from the dash and plugged it in my center console with the same cable. To my surprise it came back up within seconds. At this point for me it was the moment of truth. I had a short USB-A to USB-C cable with 90 degree ends that I wanted to use in my center console so everything was nicely tucked out of the way. I said my prayers, held my breath and unplugged it again and plugged in the cable I wanted to use. It worked! At this point I reconnected my watch and it has continued to work for the past couple days and about 10 trips. Everytime I get in the truck it is running in about 10 seconds and goes straight to Android Auto. Everything operates exactly as if plugged in. Dash indications are the same as when plugged in (Android Auto arrow turns blue).

Now, after all the time invested I'm glad it's operational. At some point I will probably try to turn off passthrough and see what happens as I'd like to remove the tap limit, but right now I'm just enjoying not having to get my phone out and plug it in every time. Hopefully this is helpful to a lot of people. I did this a few days ago and think that I've included everything I did. If there is a step I remember later I will edit it accordingly, but I believe this is everything.