car is at operating temperature and both heater lines are hot but I have the blower on five and its barely warm. its even cool on the passenger side.
Sounds like you have a stuck air blend door, either the servo has stopped operating or something has jammed the door.
I agree. Blend door or blend door actuator issue.
Search Chevrolet Impala Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Chevrolet Impala Experts