Insufficient heating (with heater) (Heating/Air Conditioning)

Diagnostic Procedure 

• 1.Check the coolant level
• 2.Check the radiator cap
• 3. Check the engine coolant temperature (ECT) during normal operation with the HDS
• 4. Check the heater core inlet hose temperature:
• • If it is COLD, check for restrictions in the hose, a damaged or leaking thermostat, or a damaged or leaking water pump
  • If it is HOT, check for restrictions in the heater core. Back flush or replace the heater core
• 5.Do the air mix control motor test - Refer to: Passenger's Air Mix Control Motor Test Air Mix Control Motor Test 
• 6. Check the blower motor unit for obstructions
• 7. Check for air leaks around the ducts and vents

Also Check for 

• HVAC DTCs