Mechanical Problems

WARNING: This page is about a different car, the 2004 Dodge Dakota. However, it is still accessible from the selected car via links, so may be relevant.

Possible causes of insufficient heat due to mechanical problems are as follows:

Inoperative blower motor.
Faulty A/C-heater control.
Obstructed cowl air intake.
Obstructed heater system outlets.
Blend door not functioning properly.
Blend door binding.
Faulty blend door actuator.
Faulty A/C-heater control.
Faulty related wiring harness or connectors.
Improper engine coolant temperature.