AudiTinkerer

Hey guys, I'm new here and had a question about upgrading my A4 infotainment system. I bought an MIB3 setup on ebay (the two main boxes and a nicer MMI screen) but I wanted to make sure they work properly on a workbench before putting them in the car. Does anybody have info on a test bench setup just to get them booted? I can't seem to find too much info on how the two boxes are wired together outside of a car, or even just the wiring diagrams would be great. Thanks so much for any help in advance!

SMac770

Wiring diagrams and workshop manuals are available from Audi. erwin.audiusa.com, pay for a day, get all the PDFs for your VIN. There's just the one wiring diagram document for the vehicle generation.

Which you don't say anything about your car other than A4. This is some B9.5 MIB3 retrofit to a B9.0 MIB2 vehicle?

What two boxes? There's the J794 main unit. The E380 control head. The J685 display. That's all you really need for the basic J794 operation. Plug a bypass loop into the port on the J794 so the optical ring is complete (though no other members on it). Do you not have the harness that connects the two accessory devices to the main unit?

drgertol

@AudiTinkerer : You're going to need the control panel & CAN gateway, in addition to the harness; see, for example: https://forums.ross-tech.com/index.php?threads/27546/
Consider this for the bench harness: https://www.aliexpress.us/item/3256801842395472.html
Another useful reference: https://forums.ross-tech.com/index.php?threads/5918/ --g