Strange UConnect issue on new-to-me 2019

[beemer]

Hi all, been creeping on here the last few months while we've been truck shopping. A few weeks back we finally found exactly what we were looking for, a 2019 2500 tradesman with the upgrades we were looking for and low miles.

The only thing I didn't like was the aftermarket android auto head unit. It worked fine, but it was too confusing, didn't have any of the vehicle settings for the lights and horn, and didn't use the factory camera.

I ordered a take-off 5" uconnect off ebay and put it in yesterday. Everything works perfectly except the volume control. The knob works, and the volume number changes on the screen, but the volume is stuck on fairly loud. I tried a soft reset with the power/tuning button but nothing happens. I disconnected the negative cable last night for about 3 hours and reconnected it without turning the truck on. I'll check it this morning but I'm assuming it won't work.

Anybody have any idea how to fix this?

I don't think it's an issue with the uconnect, the dealer we got it from said there was a volume problem and they'd added the android HU because of it. This truck has the ANC if that matters. TIA

 

[beemer]

Also, the fade/balance don't seem to be working. I can't hear much coming from the fronts, and don't hear the parking sensors anymore. Everything worked great with the android HU.

Update: I pulled both the pos and neg battery cables for about 20 minutes and still no changes. Checked fuses and everything looks ok. Pulled the radio again and nothing looks molested or broken. But still no volume control. I poked around thinking maybe the PO had an amp installed somewhere but I don't see anything. Looks like they did add components to the front so maybe an issue with the crossovers. I'll try pulling them later when I have time, but still doesn't really explain why volume is stuck almost maxed out.

There is an anc bypass cable installed, going to take it out tomorrow and hook the anc module back up. Also ordering a different bypass cable to see if that helps.

 

[beemer]

Played with it a little more today. Took the anc bypass out and hooked up the module again, no changes. Rear speakers still work, nothing from the fronts. Fader/equalizer still don't seem to be working. The front speakers door beep though if I push the vr button on the wheel so they're connected. I've got another anc bypass coming in the mail this weekend. I'm assuming it won't make any difference, but I'll probably hack it up to test the speaker level output from the HU, and also check impedance of the front channels. Really don't want to go back to the aftermarket head unit