My heating/air conditioning fans only run when turned on high. I get nothing on the first 3 settings. Any ideas? Quick fix, or big bucks?

 

the resistors in the fan speed controller for the first 3 settings are burned out...not that much to fix

 

I had a similar problem with the switch always staying on the "defrost" mode if it was ever turned on. Then I realized it was a vacuum hose crack. I don't know how I found a 1/8" hose. Not sure but, maybe avacuum hose.