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Greg A
Greg A, Master Troubleshooter
Category: Chevy
Satisfied Customers: 7882
Experience:  Working with Electronics & Cars for 25+ Years
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2001 chevy lumina: heater core..water pump..gets air

Resolved Question:

I have a 2001 chevy lumina I replaced the heater core thermostat and water pump now my heater does not blow hot air if fan is on 0 it gets warm but if you turn up the fan to 1 or above it blows cool air do you know why
Submitted: 8 years ago.
Category: Chevy
Expert:  Dan replied 8 years ago.
Is the coolant system full of coolant and circulating per design with no air in the system? Did you open the bleeders while filling the system to allow air to escape?
Customer: replied 8 years ago.
Reply to Dan's Post: Yes on both questions There appears to be no air in the system no foam or bubbles in the antifreeze and I opened both bleeders while filling
Expert:  Greg A replied 8 years ago.


Did you feel both heater hoses once the car is up to normal operating temperature?

If so, are they both HOT?


Customer: replied 8 years ago.
Reply to Greg A's Post: yes checked hoses and they both are hot
Expert:  Greg A replied 8 years ago.

Hi again,

OK. If you have heat to the hoses (and therefore the core), then I suspect that the actuator (motor) for the temperature control is not working.

Here is the schematic and the "logical diagram" for where this actuator is.



The first thing I would do is check the HVAC fuse (with a test light of multimeter) and make sure it has power on both sides. If that is OK, I would look at and feel the actuator and check to see if it is moving when the temperature control is moved (with the key turned on). If not, then I would check for voltages at the connector to the actuator.

This is where the documentation gets strange, I don't remember what is correct on this particular model car. The service manual shows the actuator both under the hood and in the passenger compartment. I suspect it is in the passenger compartment, based on the procedure to replace it. So I will send you the procedure and you can let me know if this is not right.

Temperature Actuator Replacement LH

Removal Procedure

  1. Remove the right instrument panel insulator.
  2. Remove the instrument panel compartment (glove box).
  3. Disconnect the electrical connector at the temperature valve electric actuator.

  4. Remove the bolts that secure the temperature valve electric actuator to the HVAC module.
  5. Remove the actuator from the vehicle.

Installation Procedure


  1. Install the he temperature valve electric actuator.
  2. Position the temperature valve electric actuator, then align the slots in the electric actuator driver to the flats on the temperature valve shaft.


    Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.


  3. Install the bolts. Tighten

    Tighten the temperature actuator bolts to 1.5 N·m (13 lb in).

  4. Connect the electrical connector at the temperature valve electric actuator.
  5. Install the instrument panel compartment.
  6. Install the right side instrument panel insulator.

Here is another diagram that shows the location of the actuator inside the passenger compartment.


Here is the other diagram that shows the actuator under the hood.

Engine-Compartment.gif" border="0" alt="graphic" width="784" height="686"/>

Since you have the car with you, you should be able to tell pretty quickly which location is correct.

Please let me know what you find.

Take Care, Greg A.

Greg A, Master Troubleshooter
Category: Chevy
Satisfied Customers: 7882
Experience: Working with Electronics & Cars for 25+ Years
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