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The posters on this forum have been a huge help in the past, and I am hoping y'all might have some suggestions regarding the below problem:

Wife has a 2008 Impala LT, with dual temperature control.

Temperature control works fine on passenger side; driver side does absolutely nothing; no heat comes out of register.

No noises coming from under the dash; no clicking; nothing.

Did some searching, multiple sources suggest recalibrating blend doors.

One source suggested using a scan tool. I am DIY, don't have a scan tool, so I chose option #2:

Pull two HVAC fuses from under the hood - and this is where the Impala is making me nuts - there are no HVAC fuses under the hood, or in the interior fuse block. Nothing remotely referring to HVAC, save the A/C compressor fuse.

I pulled four fuses underhood, labeled FAN - with no effect on the HVAC system.

This thread comes after a couple of hours of searching. How do I re calibrate blend doors? There are no HVAC fuses, or anything labeled HVAC.

I usually have enough sense to figure things out when they go wrong, but this problem has me shaking my head.

Can someone help me out? Thanks in advance :eek:k3:
 

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The posters on this forum have been a huge help in the past, and I am hoping y'all might have some suggestions regarding the below problem:

Wife has a 2008 Impala LT, with dual temperature control.

Temperature control works fine on passenger side; driver side does absolutely nothing; no heat comes out of register.

No noises coming from under the dash; no clicking; nothing.

Did some searching, multiple sources suggest recalibrating blend doors.

One source suggested using a scan tool. I am DIY, don't have a scan tool, so I chose option #2:

Pull two HVAC fuses from under the hood - and this is where the Impala is making me nuts - there are no HVAC fuses under the hood, or in the interior fuse block. Nothing remotely referring to HVAC, save the A/C compressor fuse.

I pulled four fuses underhood, labeled FAN - with no effect on the HVAC system.

This thread comes after a couple of hours of searching. How do I re calibrate blend doors? There are no HVAC fuses, or anything labeled HVAC.

I usually have enough sense to figure things out when they go wrong, but this problem has me shaking my head.

Can someone help me out? Thanks in advance :eek:k3:
According to the drawing I found, there's a 10A fuse under the hood labeled DISPLAY . It comes out on pin B3 to a red/white wire. You probably can't see the pin # nor the wire color, but I throw that out just in case it's needed.

This circuit provides power to the HVAC CONTROL MODULE. So I'm thinking that's what you're looking for.

That said, I think most folks just disconnect the battery. But that 10A fuse should suffice.

HTH.

Doug

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Discussion Starter #3
Many thanks Doug! I'll give that a shot, and update the thread with my findings...
 

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Discussion Starter #4
I'd hoped to repair this successfully, and post my findings on this thread, so that it might help someone in the future.

Pulling the fuses did nothing.

And even after pulling both battery cables, the blend doors would not reset. Did not hear blend doors resetting themselves, after reconnecting power.

And then...24 hours after pulling both cables, the driver's side blend door started working again. Car now has heat (?!)

Perhaps it's a bad actuator, even if there's no clicking associated with it?
 

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And then...24 hours after pulling both cables, the driver's side blend door started working again. Car now has heat (?!)

Perhaps it's a bad actuator, even if there's no clicking associated with it?
You can have a bad actuator without the clicking. I'm glad to hear it's working again. But keep your fingers crossed.

That said, years ago I took one out of my 07 and took it apart. I repositioned a couple of the gears (to rotate the stripped teeth out of play) and it's been working ever since. So every once in a while, these things can be healed
without replacing :eek:k3:

Doug

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Discussion Starter #6
Thanks so much, Doug! I'll remember that rebuilding it is an option, if it goes goes out completely
 

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2008 Impala base 3.5 model was not blowing any heat out of my defogger vent and floor vent, only out of upper dash vents, regardless of setting. With the key in the off position, I pulled the 10 amp DISPLAY fuse as noted above from the fuse panel under the hood and waited about 2 minutes. Then I replaced the fuse and turned the key to accessory position to fire up the dash. I was able to hear the actuators resetting and after the noises stopped I turned the car on and attempted each blower setting. And, they all worked fine after that. So, in my case, luckily, the easy fix worked this time. Thanks, all, for the tip!
 

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2008 Impala base 3.5 model was not blowing any heat out of my defogger vent and floor vent, only out of upper dash vents, regardless of setting. With the key in the off position, I pulled the 10 amp DISPLAY fuse as noted above from the fuse panel under the hood and waited about 2 minutes. Then I replaced the fuse and turned the key to accessory position to fire up the dash. I was able to hear the actuators resetting and after the noises stopped I turned the car on and attempted each blower setting. And, they all worked fine after that. So, in my case, luckily, the easy fix worked this time. Thanks, all, for the tip!
Always great when the easy thing does the trick and having a place like here to find those!
 

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2008 Impala base 3.5 model was not blowing any heat out of my defogger vent and floor vent, only out of upper dash vents, regardless of setting. With the key in the off position, I pulled the 10 amp DISPLAY fuse as noted above from the fuse panel under the hood and waited about 2 minutes. Then I replaced the fuse and turned the key to accessory position to fire up the dash. I was able to hear the actuators resetting and after the noises stopped I turned the car on and attempted each blower setting. And, they all worked fine after that. So, in my case, luckily, the easy fix worked this time. Thanks, all, for the tip!
 

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2008 Impala base 3.5 model was not blowing any heat out of my defogger vent and floor vent, only out of upper dash vents, regardless of setting. With the key in the off position, I pulled the 10 amp DISPLAY fuse as noted above from the fuse panel under the hood and waited about 2 minutes. Then I replaced the fuse and turned the key to accessory position to fire up the dash. I was able to hear the actuators resetting and after the noises stopped I turned the car on and attempted each blower setting. And, they all worked fine after that. So, in my case, luckily, the easy fix worked this time. Thanks, all, for the tip!
did that and everything was perfect again, thanks
 
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