I think you need to completely power off, from battery, and when it reboots, it will recognize it as a source, if its hooked up and power on., as in RF input to 959.
I bought mine brand new in 1990. So at least that old.
because when you drive theair is pushing on your car and goes inside the car and goes warm and heats up as you go
The Mazda 323 of that time from had a 1600cc engine but that isn't going to effect the issue of where to get a wiring diagram. Haynes makes a manual for the 1990-1994 Mazda 323. If you have a 1986-1989 Mazda 323, you will need to get a FSM (Factory Service Manual).