headunit not getting power

Whats up guys .. Okay I've had an aftermarket stereo for a long time but then it broke and so I've had the stock HU in for the past three months. Well today I decided to get another aftermarket unit again... I started hooking up the new unit to the wiring harnesses I had and it came on temporarily because I had not yet fully secured the wires. But then all of a sudden I couldn't get ANY power. So I hooked the Stock HU back up but now only the clock comes on for a minute or two ... it can eject and accept cds but it still doesn't appear to have power. It's all hooked up stock again and the AUDIO fuse on the side of the door is brand new. I've tried everything I could think of plus searched the forums... Any idea on whats going on? Or What I'm missing? Thanks in Advance!

sorry I copied and pasted from a car specific forum .. 2005 Ford Explorer Sport Trac

The fuse you need to locate is probably going to be labeled Radio.  The radio requires 2 power sources to come on.  The fuse labeled Audio is for the constant voltage to the radio and for the OEM amplifier.  Look for a fuse labeled Radio.  You are missing the switched/accessory voltage.Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB