The temperature dial doesn’t have any effect on the heat of the air blowing out. Basically the heater doesn’t work. When we are running the air conditioner, we can get colder or less cold air with the dial, but if we want to warm things up, turning the dial to the right (toward warm) does not warm up the air. This happened intermittently at first but now it just never warms up anymore.
Well, I guess you will have to have it fixed .
Is the engine’s cooling system full? Low coolant level will affect the heater performance.
Here is a good DIY checklist for that.
It sounds like your heater core could be clogged, but there are also other possible causes that would be less severe, like problems in the duct work or a relay.
Blend door not working right .