# Headlights dim/HVAC fan slows when braking 14 Cruze



## Dcoxjr (Mar 8, 2014)

I have a 14 Cruze with an interesting issue. When I brake somewhat hard, the HVAC fan will slow down for a brief moment and the headlights will dim. This has been happening since I drove the car of the lot with 13 miles on the odometer.

I've had the car in 3 times so far. First, they tightened some wires and cleaned some grounds. Second, they replaced the fuse box and battery cables. Third, they told me it was operating as expected.

I did drive another 14 Cruze and it did the same thing. I have it on video and am considering posting it.

I'm having a really hard time believing a brand new car with dimming headlights is normal. The dealer won't do anything else. Is anyone else seeing this issue?


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## spacedout (Dec 7, 2010)

Are you setting off the ABS when you are braking hard? The reason I ask is this is the only time I have ever experienced what you are describing. 

I have noticed the lights will pulse with the abs when they appear dimmed, as though the ABS system electrical draw is ridiculous. BTW this is not the only car I have noticed this happen with.


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## au201 (May 18, 2013)

"Braking hard"...hard enough to engage ABS? I've noticed ABS pulls a lot of current when active and can dim the lights. Also could be the "brake boost" function where if the computer detects a panic braking situation it adds brake force through the ABS module to assist in stopping. That could also be a source of power draw. 


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## jblackburn (Apr 14, 2012)

spacedout said:


> Are you setting off the ABS when you are braking hard? The reason I ask is this is the only time I have ever experienced what you are describing.
> 
> I have noticed the lights will pulse with the abs when they appear dimmed, as though the ABS system electrical draw is ridiculous. BTW this is not the only car I have noticed this happen with.


Same - driving back in a snowstorm late one night, I noticed my Volvo S70 doing the exact same thing. It creates a huge draw on the electrical system. 


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## Dcoxjr (Mar 8, 2014)

The abs isn't engaging that I can tell. It happens when driving around town where the speed limit doesn't get above 35.


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## obermd (Mar 3, 2012)

I suspect you're braking hard enough to trigger the ABS system but not quite hard enough to actually have it pump the brakes for you. When active, ABS draws enough power that the battery simply doesn't have enough voltage to drive all the electronics in the car. As a result headlights will flicker and the blower will turn on and off. Fortunately all the systems in a car are direct current so the ABS triggered brown outs won't damage them.


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## Dcoxjr (Mar 8, 2014)

This does make sense. I had taken the service manager for a ride and he confirmed there was an issue and proceeded to attempt to figure it out. After 3 service calls they simply said it was considered normal operation with no other explanation. I've just been struggling with accepting dimming headlights as being normal. The ABS theory makes sense although I would have expected the service department to have known that or at least offered it as a possibility.

All in all...not impressed with the service I received from the dealership.

Thanks so much for all the replies! Much appreciated!


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## Blue Angel (Feb 18, 2011)

Dcoxjr said:


> When I brake somewhat hard...


I think we need a little more elaboration on what "somewhat hard" means. Your lights should not dim appreciably if you are just pushing the brake pedal enough to get the brake lights to come on.

If you are braking hard enough for the ABS system to activate then everything the other members said applies. It's very possible the ABS pumps start-up at some pre-determined braking force so they are ready to go into action if needed, before the tires actually start to slip.

Does your 2014 have a voltage display on the DIC? If so you could watch how much the voltage is dropping.

The fact you validated the same issue on another car is a pretty good indication nothing is wrong. I have not noticed the same thing on my '12, but I am generally very easy on the brakes and there's a real possibility that there are changes to the car's calibration between years.


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## Dcoxjr (Mar 8, 2014)

I'm definitely referring to a quick stop although not hard enough that the passenger is thrown against the dashboard.  I have to admit that I do tend to stop over short distances rather then allowing for a more gradual braking. Still, I encounter this issue almost daily.

I do believe there is a voltage display...I'll have to take a look. The dealer did say there wasn't enough voltage but he said it was do to the decrease in RPMs.


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## Dragonsys (May 27, 2013)

Dcoxjr said:


> I'm definitely referring to a quick stop although not hard enough that the passenger is thrown against the dashboard.  I have to admit that I do tend to stop over short distances rather then allowing for a more gradual braking. Still, I encounter this issue almost daily.
> 
> I do believe there is a voltage display...I'll have to take a look. The dealer did say there wasn't enough voltage but he said it was do to the decrease in RPMs.


A quick stop will turn on (activate) the ABS, even if it is "not hard enough that the passenger is thrown against the dashboard"
ABS will activate without actually engaging and pulsing the brakes. When it activates there is a large draw on the electrical system (lights can and usually will dim), when it engages there is another draw which is what will causes the lights to flicker.

This is normal for the majority of the cars with ABS systems installed. If you brake hard and short (which is bad for MPG and will wear your brakes out faster), you will be activating ABS, and since you say this is how you normally brake, you should normally see it

Also, the Voltmeter shows the charge being sent out by the Alternator, not the charge currently in the system. So if everything is working you probably will not see a drop on the Voltmeter, or not much of one. Also, IIRC the Cruze charges more when breaking, so you might actually see a spike


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## Dcoxjr (Mar 8, 2014)

So just for curiosity sake, I switched the display to the voltmeter. When the blower cuts out, it drops from 14.7 to 14.0.


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## aperry1996 (Dec 13, 2016)

Has anyone found a fix for this?? Is it a ground cable update? Thanks


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## jblackburn (Apr 14, 2012)

aperry1996 said:


> Has anyone found a fix for this?? Is it a ground cable update? Thanks


http://www.cruzetalk.com/forum/25-g...al-coverage-14311-negative-battery-cable.html

There's an extended warranty coverage to replace the cable. Just say that you are having electrical issues and the dealer should replace it under the campaign.


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## aperry1996 (Dec 13, 2016)

thank you


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