On your humming noise- sounds like you have a bad hub bearing. Can you tell which side of the vehicle the noise is coming from? Raise the front wheels and check the bearings for looseness. That may contribute to a shake in the front end. Also check the condition of the tires. Tires are the leading cause of vibrations- hows the alignment? If not sure about the tires, I suggest taking them to a repair facility to have checked and maybe re-balanced. The condition with the blower sounds like a resistor problem. Check the power and ground at the motor when changing the fan speed. You could also have a weak blower motor. Check that first then you may need to verify power at the switch. Most likely the switch will be good. Let me know how that goes. | 
