I have a 97 that up until now seemed mechanically sound. Lately when I try to run the heater, it will never get hot. I try it manually and on auto. The fan seems to run but the air never gets hot and if I run it on auto, it never seems to do anything. When you look in the main vent, the big one above the center column, it appears to have a baffle several inches inside of the vent. This baffle never opens.

Has anyone had a similar problem? I am planning on taking it to a good A/C shop but I would like to have an idea of what is wrong before I take it so I don't get ripped off.

It does not throw any DIC codes either.

Thanks in advance for your help.

 

Sounds like the heater core might be going out since it isnt getting hot. For the baffle or door to not move, it is a malfunction with the door actuator not opening.

 

You're heater core might have been damaged. Proper maintenance of it is very important. When the coolant sprung leaks, that's one indication that there's something wrong with your heater core. My dad didn't replaced his Mercedes heater core, it had affected his car's cooling system. Replacing damaged heater core immediately is a wise action. And get a good quality of it!

 

Now wait a dog gone minute That info doesn't seem to pass the common sense test!

There are metal and rubber hoses that connect the HVAC heater core (which is buried inside the HVAC ducting system):



Here is the HVAC entire duct system removed for your viewing:



















If you feel the metal and rubber hoses and there HOT,,,,you have heat!

You may NOT be able to control the servo motors that allow you to use that heat!

To easily figure out what happening or in your case NOT HAPPENING is to read your DTC's! (Man,,,there needs to be a GIANT pop-up that says:

HAVE YOU READ YOUR CODES BEFORE YOU POST

Anyway,,, hear is how to read your DTC's:

This is the absolute best C5 Diagnostic Trouble Code (DTC) web site!!!

http://www.corvettedoctor.com/Code_Main.html
http://www.corvettedoctor.com/index.html


Go to “technical data base” and then to “Corvette ECM Computer Codes”. Then select your year car. Read the instructions and then scroll down to the "READ MORE" window to view the code definitions.\

Here is another very good site:

http://www.obd-codes.com/trouble_cod...d-ii-codes.php

Make sure to include the H or C suffix!!


Write down and post your DTC’s Then clear them ALL!

Sound effects are cool too! 

Your HVAC system is monitored by the DTC computer. If it is malfunctioning, it will tell you.

If you do not have the ability to control heat or cooling, here are the components that are NOT working correctly:





Read and post your DTC's and then clear them. After you clear them,,see if the heat/cooling works correctly or if the DTC returns. post the DTC that you get on the second reading.

BC

 

BC - you must have overlooked this part of my post:

I appreciate the help though.

 

KLBean - the car has no leaks that I can find. I am not sure if you were talking about my car or using the other as an example.

 

Stuck thermostat?

 

Bill is right on the money as usual! His photos (the two near the bottom of his post) show the temperature controller motor. It is an electrical device that controls the temp setting from cold to hot. Since it's electrical, it's entirely that there may be either a blown fuse or the controller itself is toast.

 

Try doing a controler reset. You can pull the HVAC fuses and then reinstall them or you can just disconnect the battery for a minute or two nad then reconnect. After you disconnect the battery check and clear the DTC's (sometimes disconnecting the battery sets codes)

See if that makes a difference.

BC

 

Okay, I have some additional information. I originally thought the unit would not blow warm air at all. It will blow warm air on defrost with no problems. On auto or manually via the dash vents is where the unit only blows cold air. This all started around the time I changed my battery. I read somewhere that there are vacum lines that can become unplugged or damaged that are located under the battery.

Any thoughts on that?

Thanks,

Shannan

 

TRY THIS!!:

 

A previously leaking battery can be a possible culprit too. Check all the vacuum lines, etc beneath the battery as well.

 

Sounds like an air blend door servo motor to me(hot from defrost not face vents). Battery replacement could have screwed up the calibrations. Do a reset like Bill said.

 

Thanks bill. I will try the reset tonight.

Shannan

 

How did the reset do? I have a similar issue with no heat on the drivers side but the passengers side is fine. No codes thrown.

 

OK,,,the vacuum from the manifold "ONLY" effects the vent selection feature of the HVAC System. If you can change the vents from lower to bi-level to upper to defrost,,,,you have adequate vacuum!

Temperature is controlled by the two servo motors.

BC

 

Awh....great to see the master of electrical issues online. Hey Bill, GM from SF Bay area.....recall some of the infamous wheel sensor issues alot of us went through and you counseled me and hundreds of others on.......guess what, mine fixed itself..... That's a first...but welcomed none the less....

but now, this same kind of deal for me.... no codes at first, but now I do throw B0441 and it won't go away upon resetting and checking all fuses and battery connections. Looks like I join the failed actuator group of vette nuts...

any other ideas?

 

I am so glad I have a C60 (manual) and not the CJ2 (automatic) HVAC system.

 

bought an acutator from gmdirect, slapped it in and the problem went away