Eonon GA7166A - Multiple Problems

[samer0214]

I purchased this in 2017 and installed it in my 2005 e53 4.8is, then had to take it out because audio stopped working. No sound can be heard regardless of source. (BTW, car is equipped with factory DSP).

I re-installed it last month figuring I would chase whatever problem(s) that made it stop the 1st time around, only to find out that it started working again, but.....

1) Audio only out of the front speakers
2) Radio buttons do not illuminate when the headlights are turned on. I have confirmed that the buttons do light up when the unit is 1st turned on, but then and only then.
3) Steering wheel controls: only volume up/down works. Nothing else works or can be programmed/assigned

4) Finally, the BIG one: audio stopped working altogether (AGAIN), out of the front speakers as well, after about one week of the re-install !!

What gives? What should I check? Is the problem from the unit itself or something in the car?

Eonon Customer Service leaves much to be desired.

Thank you - Samer