Hi everyone,
I’m installing the USA-630 cougar radio from classic car stereos on my '69 cougar and wanted to see which wires you all used for power. I was thinking of tapping the yellow/black from the original radio wiring for key-on and using the cigar lighter blue/red for constant power. but for some reason the radio still didn’t turn on. Then I went to the fuse box to see if I had an accessory post but I don’t and there is no fuse even in the accessory position.
Thank you for any advice!
If you have voltage on both wires it should work. Of course you also need to connect the ground.
Give the new radio a good separate ground as XR7428 suggests. When I replaced an incompetent 1990s aftermarket replacement radio in my '68, I found the bozettes who did the install had not ruined the Ford power connection. I added a jumper for a ground anyway!
R.B.
You also need to have the antenna plugged in to receive any signal.
Randy Goodling
CCOA #95
Bozettes: I love it! 
I’m sure you know this, but the factory car side plug is one wire switched power for the radio and the other is power to the dial light. Ground is through the chassis, and may not make good contact when not installed completely.
Thanks everyone! Got her working. I do think the grounding ultimately was the issue 