Possibly but but not for long. The 12v motor will draw more current than the 9v battery can supply and the undervoltage will cause the motor to run hotter than normal thus shorting its usefull life.
You can but the motor may not run, however you will not burn the motor.
Unless it is a 12 volt DC box fan you cannot run it at all. If it is a 12 volt fan the time it will run depends on it's size and at what speed you run it and the condition of the battery. All you can do is try it.
For a short while, but than the fan will break because it has too much energy put into it, unless you had a converter in between. The fan will run at almost twice the speed it was designed for. Current is directly proportional to the voltage so the motor will run very hot. The extra heat will eventually break down the motor winding insulation, the windings will short out and that will be the end of the motor.
No. The motor was designed to run on a specific voltage and any variance from it will not work. The amperage of the motor is what you should be looking at. A single 1.5 volt battery neither has the voltage nor the capacity to produce any thing close to the amperage you would need to run the 12 volt motor.
the ma can be figured via Ohm's Law, or by looking at the motor's nameplate data, the h depends on how long it needs to run. mA h are battery designations.
Run a wire from the positive terminal on the battery to the fan motor. If the fan will not run when hot wired, the motor is burned out and will have to be replaced. If the fan will run when hot wired, check the fan motor fuse. It us probably in the engine compartment near the battery.
If you can get the battery to run the motor, write it up in a science journal. You'll be rich. Sure but what are you going to use to power the 12 volt motor? You will have to use another battery which you could just use to power the radio in the first place.
The easiest way would be to run a wire from a 12 volt source (battery) directly into it (they normally have a two wire plug). This will let you know if it's the fan or the switch is bad.
They are not compatible. You cannot connect any AC device to a DC battery without a inverter. The size of the inverter determines what it will run. And the wattage of the fan determines what size inverter to buy.
It depends on the battery's voltage. Such a battery's capacity is given in ampere-hours, not amperes. An 850 amp-hour 12 volt battery can theoretically operate a 12 volt motor for about 12 minutes but in practice it's probably, maybe a lot less, since the motor will probably stop as the battery nears its depletion.
disconnect the connector and run a wire from the battery to the fan if it runs it is good
it can get really hot and burn the circuit