I have a a 2004 pontiac vibe and it has no heat. The coolant level is full and the thermostat seems to be ok because it does not overheat. Is it possible that that control switch might be bad? Id like to add that the a/c does work fine and blows cold air. Is there a chance that that door in the heater box is not opening? Plz help if possible.
With engine at operating temp, use a glove and touch the heater core hoses. If both are hot, then blend door or controls are broke.
If one hose is hot and the other is cold, then heater core is blocked.