# Light Sensor blinking when car is off and locked



## sprinklefurball (Jan 12, 2011)

When I parked my car in my driveway tonight and locked the door, the light sensor (that ball under the windshield, in front of the cell phone pocket) started blinking a red light and I do not know what it means I'm afraid it's going to drain the battery of my car, would somebody please explain how to stop it or at least why it is blinking like that despite the car being off and locked.
When I unlock it, it stops, when I lock it and the dashboard is still lit up, it is a solid red, but when I lock it so no lights are on it blinks red.
I hope somebody can explain this to me.


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## 70AARCUDA (Nov 14, 2010)

...it does the same thing on our car, the salesman said it's normal.


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## GoldenRS (Nov 11, 2010)

*Alarm 'ARMED' indicator* is the likely answer here..


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## sprinklefurball (Jan 12, 2011)

Weird because I had never noticed the light going off at all since I got the car a month or two ago, I had no idea that ball even lit up until tonight, nor did I even know what it was  .


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## 70AARCUDA (Nov 14, 2010)

...page 1-3 of the _Owners Manual_ describes it as:

*L.* *Light Sensor*. See _Automatic Headlamp System on page 6-3._ 

...and page 6-3 says this:​ 
*• Automatic Headlamp System* 
When it is dark enough outside and and the exterior lamps control is in the automatic position, the headlamps come on automatically. See _Exterior Lamp Controls on page 6-1._
The vehicle has a light sensor located on top of the instrument panel. Make sure it is not covered, or the headlamps will be on when they are not needed. The system may also turn on the headlamps when driving through a parking garage or tunnel.​ 
...but, page 2-10 has the answer (ta-da)!​ 
*• Immobilizer Operation*
This vehicle has a passive theft-deterrent system. The system does not have to be manually armed or disarmed. The vehicle is automatically immobilized when the key is removed from the ignition. The system is automatically disarmed when the vehicle is started with the correct key. The key uses a transponder that matches an immobilizer control unit in the vehicle and automatically disarms the system. Only an authorized key starts the vehicle. The vehicle may not start if the key is damaged.​ 
The *security light*, *located in the **instrument panel cluster*, comes on if there is a problem with arming or disarming the theft-deterrent system. When trying to start the vehicle, the security light comes on briefly when the ignition is turned on. If the engine does not start and the security light stays on, there is a problem with the system. Turn the ignition off and try again. If the engine still does not start, and the key appears to be undamaged or the light continues to stay on, try another ignition key. If the engine does not start with the other key, the vehicle needs service. If the vehicle does start, the first key may be damaged. See your dealer who can service the theft-deterrent system and have a new key made.​ 
Do not leave the key or device that disarms or deactivates the theft-deterrent system in the vehicle.​


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## sprinklefurball (Jan 12, 2011)

Yeah I saw that in the book but I'm still at a loss as to why it is doing it when the car is off.


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## LARRY01Z28 (Dec 4, 2010)

i dont think mine does that.


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## FanDamNCSU (Dec 23, 2010)

Mine does it. I believe it's actually just to tell you and warn others that the integrated security system is active - The light flashes from the ball shaped object on the dash near the defrosting vents.


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## SilverCruzer (Nov 30, 2010)

Yes, that's HAL's eye.


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## SingBam (Jan 11, 2011)

Mine does it as does my folks Subaru Forrester, brother's VW Tiguan and my former car (a Nissan). It is related to the security system being on as far as I know. Its pretty common on new cars. Saw it on a BMW parked next to me this evening.


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## 70AARCUDA (Nov 14, 2010)

SilverCruzer said:


> Yes, that's *HAL*'s eye.


...you've seen "*2001: A Space Odyssey*," I can tell.

...remember this?

*I*-1 = *H*
*B*-1 = *A*
*M*-1 = *L*


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## trol (Dec 4, 2010)

It's for the anti theft system showing it is "armed". It is suppose to also act as a deterrent for crooks to show that you have an alarm. 
So if you don't lock the doors, it shouldn't flash. Also to show you it is armed and locked up.


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## spacedout (Dec 7, 2010)

On my 2004 cavalier there is a red blinking security light in instrument cluster when alarm is armed. To arm the alarm all you need to do is lock the doors with the remote key fob. when you do the headlights blink/flash. 

If I lock my doors via the door lock button(in the car) it does not arm the alarm, just locks the doors. someone with a Cruze should see if it arms with the doorlock(not on remote fob), I would suspect it doesn't.


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## scaredpoet (Nov 29, 2010)

The manual isn't very good at explaining it, but that red light IS the security system letting you know it's armed.

You don't need to worry about it, that light in itself isn't going to run down your battery. There's lots of other subsystems in the car (OnStar, the ECM, just to name a couple) that are drawing a lot more power than that red light, even when the car is "off." The electrical system is designed to handle those loads and still give you plenty of charge to start up again.


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## turbocruiser (Sep 10, 2011)

*Automatic Lights too sensitive*

Recently I have noticed that my lights are switching from DRL to full lights on, when I am not in bright sunlight, or the sun is behind me. They were not this sensitive in the past. Now if I am in the shadow of a big truck, or it isn't a very bright day, the system switches. Has anyone else had this problem. I am thinking the "ambient Light sensor" or "sunload" sensor, as it is sometimes called, is going bad. I hate to go to the dealer, as they will likely say they cannot find the trouble, and I'll waste the day. The sensor is pretty cheap ( I found them on line for about $10.00), but I'm not sure how it comes out of the dash. The repair manual procedure is 1. un-clip from dash 2. disconnect electrical connector. Sounds simple, but you know how manuals can be. Any ideas?


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## rafaelmd (Jul 27, 2013)

Yes, just remove it and change it.... its that easy yes...

anyone knows how to retrofit a AMBIENT LIGHT SENSOR to a chevy cruze LT that doesnt have it? so it would turn the headlights in the dark!!!
I tried, used the LTZ button and the LTZ sensor... without success... plug and play seems not to be the case...

How to program the BCM to make this work?? Maybe its not connected to the relay???

thanks!


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## Merc6 (Jun 8, 2013)

rafaelmd said:


> Yes, just remove it and change it.... its that easy yes...
> 
> anyone knows how to retrofit a AMBIENT LIGHT SENSOR to a Chevy Cruze LT that doesn't have it? so it would turn the headlights in the dark!!!
> I tried, used the LTZ button and the LTZ sensor... without success... plug and play seems not to be the case...
> ...


What year and country are you in? Are you saying you don't have auto on lights in your Cruze from the factory?


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## Deynaynay (Jul 18, 2016)

If you look in your owners manual it will tell you everything you need to know about that security light. Mine explained that when it's off the vehicle's alarm system is not activated, slow flashes mean it is activated, and fast flash shows a problem with the alarm system.


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## kkscott7480 (Apr 27, 2018)

SilverCruzer said:


> Yes, that's HAL's eye.


good answer


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