# Defroster questions



## McNeo (Dec 17, 2013)

Two unique questions, both repeatable and testable.

First, every car I've ever owned before the Cruze, the rear defroster is on a 10 minute timer. Hit the button, it runs for 10 minutes, then shuts off. Done. The Cruze seems to run for a random period of time anywhere from 2 minutes up to 10. I've sat in the car while it's warming up and sat in traffic long enough to know for a fact this is happening, and it's not just me losing track of time. Is there some sort of additional circuitry that controls the rear defroster? Temperature sensor, spaceage-window-clearness-sensor, etc? Is it hooked into the other HVAC controls somehow?

Second, the front defroster seems to have a mind of its own. When I first start my car I turn the blower fan to off since the engine is cold (blowing cold air inside the car isn't going to do anything anyway). Once I'm ready to go I'll put the fan on 1 or 2. Air starts coming out the front defroster but no indicator light is lit on my HVAC controls (i.e. if you hit a button the yellow light comes on to tell you where the air is coming out - all these lights are off). So I hit the defrost button just so me and the computer are on the same page. This is the first oddity. Second, I know the defroster auto-throttles to 3 to help defrost and turns down if you make a call, but outside of these situations it seems to jump around as well. When I have the fan selector on 5 and turn it down to 3 the fan seems to get louder for a few seconds before turning down. Not sure if the blower is actually going faster or if the car is redirecting air as the blower slows down or what.

Anyone else experienced any of this and have some ideas?


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## obermd (Mar 3, 2012)

I've noticed the rear defroster seems to run a variable amount of time, but it seems to be based on the outside air temps. Does Chiana have an automatic HVAC system? The manual system in my ECO MT doesn't behave the way you describe for my front defroster.


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## McNeo (Dec 17, 2013)

No the HVAC controls are all manual (aside from that standard turning up the defroster from 1 to 3 on start and lower fan speed during bluetooth calls)


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## spacedout (Dec 7, 2010)

I remote start my car 100% of the time in the winter, only time I notice the heater controls not being lit while running is when using remote start(all other dash lights are off as well). I never turn off my heater all the way though, usually leave the fan on 2 and temp dial around 1/2-3/4 turned up. 

I have heard the fan speed/output sound like it increases, but only when changing actual setting on the heater, never the fan speed. I have a 2012, so only 4 fan speeds.... feel lucky you have more than a couple usable speeds with 6 on your 2014.


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## Merc6 (Jun 8, 2013)

spacedout said:


> I remote start my car 100% of the time in the winter, only time I notice the heater controls not being lit while running is when using remote start(all other dash lights are off as well). I never turn off my heater all the way though, usually leave the fan on 2 and temp dial around 1/2-3/4 turned up.
> 
> I have heard the fan speed/output sound like it increases, but only when changing actual setting on the heater, never the fan speed. I have a 2012, so only 4 fan speeds.... feel lucky you have more than a couple usable speeds with 6 on your 2014.


When remote starting numerous GM vehicles over the years, I saw the same thing where nothing is on till you key in or press the start button. 

My speed changes for accesory mode and sometimes bluetooth.

never fully kept track but I have turned rear defrost on 3 times an a 15 minute drive now that I think about it. I wonder if it's like other cars where you lose 1 hp when it's on from the resistance and if it is varying like the set of the systems.


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## Aussie (Sep 16, 2012)

I don't have remote start, but I do have automatic climate control and just leave it set to 22C and never seem to have defrosting problems summer or winter. If I need to defrost the rear window or outside mirrors everything seems to clear really quickly so elements don't need to be on for long. Only once have I had to put the demister on whilst the car was warmed up in foggy conditions going through mountains at night. Also I have never experienced the musty smell some people have mentioned in any car I have owned.


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## jblackburn (Apr 14, 2012)

Speed might have something to do with it. I've noticed the rear defroster runs for a long time around town and shuts off quickly when I'm on the highway.

If I shut the car off with the front defroster running and turn the fan speed knob off, it'll show an "up arrow" on the radio display for air direction, but no defrost symbol. The defrost button is not lit up. Just one of those weird oddities. My fan speed is consistent with what I have it set on though.


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## Chevy Customer Care (Oct 29, 2011)

McNeo, 

I can certainly reach out to our internal resources for this question. In order to do so I will need your VIN for verification. You can send me the last 8 via private message and I will post the information I find back on the thread. 

Erica Tiffany
Chevrolet Customer Care


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## Luigi (Jun 16, 2013)

I have noticed oddities on my 2014 as well. Such as the lights not being lit when defrost is on, and sometimes after a remote start, after I put the key in, the fan shuts off and I have to turn it to 0 and back up for it to resume. I have also seen the icon on my link that shows the up arrow instead of the defrost icon. 
I have tried testing the auto fan for when in a phone call and it did nothing.. I was disappointed. 

Sent from AutoGuide.com Free App


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## brent769 (Apr 4, 2013)

McNeo,
Did you ever get the rear defroster / defogger fixed? My car (2013 2LT RS) has never run for 10mins. Usually runs for 3 mins at a time, then I have to repress the button again. Just wondering if you were able to get it resolved.

Thanks.


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