Welcome to the club. If you could add in your profile the model Bonneville that you have, it will help us help you. Do you have the automatic or manual system for your heating and a/c? Does it appear as if the fan isn't blowing hard enough, or that it is enough, but not enough heat? If you change where the air is directed, does the flow seem better? Where any of the fuses blown, or just swapped out for a test?
If you can find where it is, give it a good whack with a screwdriver, or similar and see if it starts up. We've had a few reports of the wiring going bad internally. You could also pull the connection to the motor, and see if you get 12 volts when turned to high.