I just installed the Subject unit in my motor home. I was having a problem because the always hot wire that I connected to the yellow wire was not hot, so the radio lost memory every time I turned off the ignition. I fixed the problem with the always hot wire. Now the radio stays on all the time, regardless of whether the ignition is on or not.
Accessory is only hot on 12 volts when ignition powers on, usually red. clock wire has to get 12 volts whenever cars on or off. this ones usually yellow in color, red and black go to normal positive and negative.