Stereo question

So, I installed a new aftermarket stereo in my 2015/2016 Peterbilt 579. Truck was idle with parking lights on. Stereo worked great. Shut the lights and engine off, and the stereo shut off too. With the key in auxiliary or off position, lights on or off it doesn't matter, the stereo will not turn on. I turn the key on or with the engine running, the radio only works with the lights on. Either parking or all lights on. Please, can anyone help me out here. I took the stock radio out and rewired in a new radio I bought brand new. I'm lost here. Didn't have this issue with a freightliner, and first time I've had this issue out of the hundreds of stereos I've installed.

 

The wires on the truck side are either brown or yellow. The original stock radio had three plugs. Before cutting wires, I tested all of the wires. But the only time I had on/off power, I found it is only with the key on and the lights on. Does this truck have a self ground? Or am I missing something else? All the speaker wires at the plug are brown for positive, black for ground, but the power side of the plug, the wires were either brown or yellow. And there was one green wire. Otherwise, they were one or the other. It makes little since to me.

 

I appreciate that, but it's not my truck, and the boss won't pay for that.

 

Except the problem isn't the radio. The problem is on the truck side.

 

So, it's not a fuse issue, as I have constant power to the radio for the memory wire. I should have an on/off wire that cycles with the key. But instead of cycling with the key, it only cycles with the lights when the truck has the key in the on position. If the lights are on and the key is off or in auxiliary, the radio shuts off. So you're missing the whole concept of how car audio wiring works. I posted this for someone who actually has knowledge of the trucks wiring system. I didn't have this issue when I had installed an aftermarket stereo in a freightliner, but why it's different, that's my question. So no offense, but unless you have deeper knowledge on the actual wiring, please just don't throw curveball guesses that don't mean squat. If it was a fuse, I wouldn't have power to the stereo at all.