pretty much what the title says. the fan never turns off full blast, even when the ac is off

 

This is probably the power transistor. Located behind the glove box, it controls power to the fan. I think models 1998 and later have one instead of the old resistor system. If other stuff on the control panel (such as the air outlet selection) doesn't work either, the control panel could be bad.

 

Is there an easy way to check if thats the problem and fix it? Or will I have to buy a new one

 

Unplug the transistor and measure the resistance between its two terminals that go to the large wires in the car. If it is zero ohms, the transistor is shorted.
You should also turn the key on with the transistor unplugged and confirm the fan does not start. That doesn't prove the control panel is OK though.