Blower won't go to defrost

Thanks for the update. Congrats on the repair!

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Sorry to resurrect an old thread, but my 2008 Prius just started not defrosting. Any time I select defrost it blows air out of the "face" vents. I am curious however as I just had my hybrid battery replaced and the defroster immediately stopped working. Is there any electrical correlation that I should be looking for? Just seems a little too coincidental.

Thanks for any help!

 

Does air blow out of the dash ("face") and floor vents correctly when those modes are selected? Do you hear any unusual sounds under the "center left" dash area when defrost is selected?

My first thought is that there is some fault with the mode control servo- or possibly the mode air door itself.

Diagnosis might require a capable scantool to view codes and data for the A/C system. There's no calibration for the A/C so working on the battery shouldn't have had any affect.

Posted via the PriusChat mobile app.

 

No unusual noises. I'll check the floor vent for certain when I get home, but from what I've seen any time the front defrost is chosen (either by itself or in conjunction with the floor) the dash vents are the ones blowing the air out. I do have a basic scan tool that I could hook up and see if it is throwing codes and hopefully discover whether or not I'm doing a tear down project one of these weekends. Just wanted to make sure there couldn't be something electrical that would have been messed with during the repair.

Thanks for the reply!

 

Was the dash disassembled? When the dealer did that to my car it came back with the air outlet selector nonfunctional - because they forgot to plug the electrical connector back in. The giveaway is that it doesn't matter what the outlet setting is, the air always blows out the same. The second clue is that there are no noises when the selection changes. Normally on my car it makes some slight groaning noises when changing outlets.

 

You don't need a scan tool to get most codes from the HVAC system. Just hold down the fresh/recirc and the auto buttons while powering the car on. The MFD will show some test patterns, and then you can look for two-digit HVAC codes in the top corner.

 

Those buttons are digital...so I'm imagining there is something else I'm supposed to do?

Also, update: air does indeed blow out of the floor vents, and the sound of the air certainly changes when selecting front defrost. I'm guessing this means the actually deflector or door is the issue, and as you gentlemen have noted that's the deepest and most difficult one to get to. Sadge.

 

There are buttons on the steering wheel.