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Discussion Starter #1
I had my car into Chevy for an oil change. While I was there I asked if they could turn the after blow on. I had read that it was a simple job using their OBD tool. I guess on 2016's that's no longer true. Now they need a full hook up to their software and like most update things it could take over an hour. I scheduled an appt for Wed.

Is what they told me correct or did I get the scheduling runaround?

just wondering.

fltsfshr
 

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After blow? Got me scratching my head on that one.
My understanding is that it refers to the fans blowing after the engine has been turned off, to achieve some target radiator coolant temperature.
 

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When I first saw the thread title, I thought it was After Glow, and thought of the INXS song.
 

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That makes sense. Only during really hot weather does the fan come on, but goes off when I shut the engine down, I guess that's normal operations.
 

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Discussion Starter #6
After blow is in all gm puters. It is meant for high humidity places to clear moisture out of the air conditioner and prevent a mold or mildew smell. If you've ever started your can and smelled mold when the air conditioner turns on, this is the cure. I live in SW Florida, it's hot and humid here. You have to ask them to turn it on. It runs the fan twice after you turn the car off.

Or so I've been told.

fltsfshr
 

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After blow is in all gm puters. It is meant for high humidity places to clear moisture out of the air conditioner and prevent a mold or mildew smell. If you've ever started your can and smelled mold when the air conditioner turns on, this is the cure. I live in SW Florida, it's hot and humid here. You have to ask them to turn it on. It runs the fan twice after you turn the car off.

Or so I've been told.

fltsfshr
I too live in S.FL....
Had it done on my wife's ATS for that reason. So far I have not seen a reason to do it on the Vette, either to cool the radiator down or drying the Air conditioner.
 

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After blow is in all gm puters. It is meant for high humidity places to clear moisture out of the air conditioner and prevent a mold or mildew smell. If you've ever started your can and smelled mold when the air conditioner turns on, this is the cure. I live in SW Florida, it's hot and humid here. You have to ask them to turn it on. It runs the fan twice after you turn the car off.

Or so I've been told.

fltsfshr
Ah, I knew the concept, but did not know the name.

My wife's ATS stunk from condensation from the AC. They flashed new code to run the fans a little after the car was turned off. However, it still could smell a little. So, we just started turning off the AC compressor about a mile or so from our destination and letting the fans continue to blow until we got there. THAT took care of it.
 

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When I first saw the thread title, I thought it was After Glow, and thought of the INXS song.
sigh, you don't want to know what I thought......
 

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If you mean "fan Run On" that is monitored and controlled by the calibration in the PCM

There is a low speed and high speed fan controls
Water temp must be over 217 F degrees when engine is shut down and if so the PCM commands the low speed of fan to 60% rotation
If coolant temp is above 266 F deg then high speed of fan is commanded

This is to protect the engine from high engine bay temps as it raises when engine is first turned off

In either case run on would be commanded ON for up to 18 minutes or less if temps drops below the 2 above values

As seen in the PCM GM calibration below :
 

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This is to protect the engine from high engine bay temps as it raises when engine is first turned off

In either case run on would be commanded ON for up to 18 minutes or less if temps drops below the 2 above values
That's good to know. So these are the default C7 parameters?

To me 18 minutes seems excessive (not that I question the General and his Minions), but if my fan stayed on for longer than 5 minutes I would be (before seeing this info) off to the dealer. I can't recall the fan ever staying on in my case after turning off the engine.
 

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Discussion Starter #13
I think this may be a different setting. From what I understand after blow only turns on the ac fan not the engine fan.

In my old car I had an AEM computer system and we had engine fan controls to cool down the engine and radiator temp after shutting the car off. Most cars that run boost use that.

Can someone clarify?

Thanks

fltsfshr
 

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After a track session in the summer months my engine fan will run for 5+ minutes after the car is turned off.

OP's fan should stay on as needed.
 

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After blow? Got me scratching my head on that one. But there will be a tech savvy member here that will be able to explain that term.
Don't worry Norm... apparently i don't get out much. I made the mistake of doing a google search... didn't see any car references listed! :uncomfortableness:
 

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That's good to know. So these are the default C7 parameters?

To me 18 minutes seems excessive (not that I question the General and his Minions), but if my fan stayed on for longer than 5 minutes I would be (before seeing this info) off to the dealer. I can't recall the fan ever staying on in my case after turning off the engine.
Yes that is correct, in all Corvettes for some years now
As mentioned 18 minutes or sooner if temps drop below the 2 trigger temp points

Reason to always raise hood after parking to quickly drop engine bay temps when hot as people forget once engine is turn off the soaked heat will spike up temp and bay gets way hotter
 

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First time for our 16 was yesterday. Front and back fans ran after shut down. Front ran a good length of time more.
 

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Discussion Starter #19
This is what I was told afterblow does. The service guy knew exactly what I was talking about.

Afterblow is a feature that dries the evaporator core by operating the blower motor after the engine is turned OFF. This reduces the amount of microbial growth that can create undesirable odors. The vehicle does not come equipped with the afterblow feature turned ON. If the afterblow feature is required due to an odor concern, it must be enabled using the scan tool Afterblow configuration function.


After the HVAC control module has been programmed for afterblow, the following conditions must be met for afterblow to operate:

•The engine has been turned OFF for at least 30 minutes.
•The ambient air temperature is at least 21°C (70°F).
•The A/C compressor operated for more than 2 minutes before shut down.
•The system voltage is at least 12 volts.
Once the above conditions have been met, the following sequence of events will occur:

 1. The blower motor will RUN for 20 seconds.
 2. The blower motor will be OFF for 10 minutes.
 3. The blower motor will RUN for and additional 20 seconds.

fltsfshr
 
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