[Connected Car] michaelk:
wiring harness investigation

so played around some today.

I've got an issue where I need to recalibrate the screen almost every time I boot. it seems the box (or card added to the radio?) forgets things and only works the bottom right corner and also seems to rotate 90 degrees at boot. The end result is unusable screen. I think carperformance is just a reseller because of their response. They're friendly and reply quickly but are really unable to help. The first answer was just randomly fiddle with screen and try to find calibrate setting and reboot- that proved impossible and on my own I discovered a 6 dollar USB mouse from the Walmart could be used to navigate to the calibrate app. When I inquired again when it got more frequent they basically said it's not normal and offered no help except to adjust a personalization setting to run calibrate on boot- that only works once that I can figure (might be related to weird time bug)- so I settled on having tasker run calibrate on each boot. I wonder if there is a battery in the box that needs changing but the warranty sticker keeps me out for not- might add an external battery to keep it alive for a longer time to minimize the rebooting

Anyway took everything apart today to double-check and can't find any connection issues. I traced the harness a bit to try and understand a little and basically, the skinny cables run the daughterboard to snag the screen output and the touchscreen input. But i wanted to figure out what is tapped from the radio harness to the large white plug on the box and see if anything going on their .

DISCLAIMER- I NEED TO CONFIRM (it was hot - laughing) but basically seems what is tapped in radio harness is:

1) power and ground also

2) L&R aux audio signal- interesting here is they tapped a single ground (physically next to the right signal) for common. Earlier i had the RAX hack and their harness used a ground for each L&R and their aux input worked all the time without the little plugin shunt thing to trick aux input. When i dug some more and found a pin diagram from mopar I found that the 'left' ground is actually labeled "aux audio device detect signal" I need to play some more to see what happens but my guess is if we put a switch on that to short it to ground then the aux would just work to avoid the hokey plug.

3) Here's the fun- holding the screen to flip inputs could be the daughterboard running things. BUT since it also reacts to the left steering wheel button pack and switches inputs itself when you need the reverse cam- i figured it reads the can bus. and sure enough, it looks like it taps CAN IHS (+) and CAN IHS (-). Very cool that it would get into the whole bus and read anything- BUT since there are other FCA vehicles that don't auto-switch inputs on revers and they have alternate connections it seems the real dev is not involved to update things to sniff for other reverse signals. Reading around here- seems that there is probably a custom serial port someplace in the box that reads this and there's probably no documentation for us to do anything ourselves. But one can hope...

---------- Post added at 06:12 PM ---------- Previous post was at 06:07 PM ----------

So the spec for the chipset for the V4 says it can handle an OTG port and a couple (maybe 3?) other USB ports. Obviously, the box only has the one USB A port visible on the pigtail. I wish we could get in the box and look for a header for the OTG port to help rooting but.... the darn warranty sticker.

on the FCA/Dodge side of things- I have a Durango with a USB port and SD card reader in the dash (USB Media "Hub" Apparently, FCA uses USB Mini B connectors to interconnect all the ports and the radio. They use latching connectors that are keyed but if you undo them there's a standard USB mini B in there. They do some odd male/female things so you have to pay attention to where you undo cables, but bottom line you can undo the connector on the back of the dash's USB port and stuff a USB mini B female on it and connect it to whatever host device you want.

I first tried an old laptop in case there's anything weird going on. My Dash "Hub" actually has 2 mini-B connectors and a multipin auto harness. Without the harness when you connect it to windows it sees a USB Hub, but the USB port was still dead. So I assumed it needs power from the harness on the back of the dash hub and connected that. UP popped up a USB mass storage device which I believe is the SD card reader- didn't get around to confirming and then the USB port also comes to life. Knowing that it was safe at that point I connected it to the USB A Host port on the box and presto chango now I have the in-dash port connected to the android tv box without any exposed wiring.

Connected the "android auto dongle" through the cars USB port and that works perfectly. I ordered a used 2 USB dash hub from eBay (later model years have 2 and will see what that does. The pictures of that also show the 2 mini B ports- I'll play some more when I get that. I'm not sure what is in those dongles but from the other folks hacking android auto into older models (by using newer radios) apparently, one port works for android auto and the other doesn't. The scuttle is its a body module programming thing but I wonder if maybe there's something physical in there and so the dongle won't be necessary any longer with the new hub? My other thought is if the two USB min B jacks allow you to connect to 2 different hosts- I would try one on the original Uconnect (in case I ever need to update the software) and the other for the android TV box.

So apparently the android tv box handles hubs just fine. As I mentioned earlier it handles a mouse or USB keyboard fine. Also, I played around and connected my hotspot by USB instead of wifi so the device sees it as a modem and that works just fine- so I assume a USB modem works out of the box too. (again odd if that works that carperformance sells a hotspot and not USB modem- like they don't know what the box can do)