My brother has a 2008 Wrangler X with the V6 engine on it. I am helping him see if we can fix this.

He states that he can't get any heat below 60 MPH. The blower works but cold air comes out. When he reaches 60mph the air turns hot.

I am trying to figure any way that the heater core is not getting flow at lower speeds. Water pump was replaced some time ago (unsure when).
Hoses seem to be connected and in good shape.

Heater core clogged? To where there isn't good flow at low pressure? Any ideas welcome.

Ok, so reading up around the internet it would seem it might be the air door actuator that opens the door tot he heat.

Still, any guess as to why it works at high speed? Is the air just pushing it open due to the speed?
I will check the actuator and see if that is the issue.