2004 nissan maxima blower motor not blowing air,

Does it not blow at any speed? If it works on med-high speed, you need to change your blower motor resistor. You can also check the fuse to see if it is blown. If you have a 12v test light and can confirm that the blower motor is getting voltage you need to change out the blower motor.

check wiring on fan and switch if you had them off. Sounds like you have ground wire mixed up with power wire.

If very little air comes from the vents, the fan on the blower motor may be damaged, or there may be a restriction in the vents, or a blend door may not be open completely.

Sounds like you have a bad connection at the blower motor plug. Have you checked under the glove box where the blower motor is? Usually has a big plug with 2 heavy gauge wires. that might be melted or getting a bad connection. Try holding the plug to one side or wiggle it to see if turns off blower. If not, check your resistor that controls your fan speed, located near the fan on your a/c ducts. Usually has a plug with 4 0r 5 wires held up by 2 screws. The wires are heavy gauge as well

The engine oxygen sensor code is a different maintenance item and has nothing to do with the cabin blower.
If you have a clogged vent, dirt-loaded heater core or stuck air door, the blower may be running while installed, but no air is moving. You did not say whether the blower was left installed or removed for your test with an independent power source.
If you have voltage on the connector to the blower, but it doesn't run when it's connected, then you have a bad connection in the connector or an open ground. Check for tarnish or dirt buildup on the connector terminals. My favorite means of removing light tarnish is a pencil eraser, but for the heavy tarnish I usually see on automotive electrical equipment I use Scotch-Brite abrasive sheet (not the kind on a dish-cleaning sponge, the kind used for metal polishing). If the male terminal is a flat blade, you can clean the female terminal by wrapping a strip of Scotch-Brite around the end of an ignition file or similar stiff strip of metal and running that into the terminal. If it appears the female terminal blades are spread too much to make reliable contact with the other terminal, try pushing them together with a jeweler's screwdriver.
It's also possible there's a sensor circuit (temperature, airflow or closed-loop motor speed control) that controls the blower that isn't working properly. What happens when you try to run it at full speed and maximum heat or cool?

If the air isn't blowing at all, the the only component that could cause the problem is the blower motor. With the fan on - check to see if you have power getting to the motor. If you do have power at the motor, replace the assembly. If you don't have power, find the cause of your open circuit.

It's time to replace the blower motor, bearing in blower motor have gone bad.

The most likely cause of your concern would be the fan control amp. It is located behind the glove box. It controls the ground side of the blower motor. But before replacing it, check to see if you have power and ground at the blower motor.

bad fan blower. have you tried it on diffrent speeds? or see if the heat blows out?

Could be one of 2 things. It could be blower motor resistor or blower motor amplifier. If you have AUTO AC feature/setup, than it will be the amlifier. If you have manual AC than I would look at the resistor, but sounds like you have AUTOAC system, so get the amlifier checked. Its behind the glove box screwed to the air box assembly. 2 screws and its out. Hope this helps. Good luck and let me know what you found.