I am pretty shocked that there is no way to simply turn the HU off. This is pretty annoying since whenever the key is in the ACC or ON position both the HU and my amp, since my amp is switched on via remote cable from the HU, come on. As a result, there is no built-in way to have the key in the ACC or ON position, and have both the HU and amp off.
Why do I care?
Because I have other units e.g. inverter, ham radio etc. installed in the car, that I would like to be able to switch on or off with the ACC or ON position on the key, but without the HU & amp always drawing power when the
