Hello I will help you with your question,
While it may be the switch thaty has failed you need to check the 30 amp fuse in the junction block #1 first and ensure that it is good and has power. You will need a testlight or voltmeter to be sure that it is working correctly. If there is power through the fuse check the relay in the same fuse box
Here is the wiring diagram so that you can see the power enter at the top of the diagram from the fuseable link to the junction block #1 under the dash and through the 30 amp blower fuse to the relay. The relay should be turned on with the ignition switch and the blower motor should have power at that point. You can use the test light to check with the key on. When you turn the blower switch on it grounds the blower motor through the
blower resistor providing a complete circuit to ground . Once the circuit is completed the blower motor will run.
Use the test light and let me know where you don't have power, I would start at the blower connector and if you have power check the blower resistor and if you do not have power check the green 30A fuse
This is a location of the fuse/junction block I don't have a legend of which fuse is which as it was not included in the service information but it should be on the cover for the box
Let me know what you find