So the last two days, my headlights are remaining on on my drive home from work. It is about 15 mins to home and there is plenty of daylight. I get off around 430pm. I keep switching the modes to see if this will make it better and nothing. Any idea on how to test the sensor? Where to get a new one? How to swap it?

I think it has to be bad. I know it also integrates the Auto AC function. I tried today on my way to work. Set the AC to auto. It was 80F outside. All my AC did was stayed set at 60FF in full blast. Is this normal? I would think it adjust to the temp/day or night. I have never used auto AC

 

With your headlights on and in Auto mode, shine a flashlight on the sensor and see if the lights go off.

The sensor is the little hemispherical 'bubble' in the dash grille next to the center speaker.

Probably an easy DIY to pop the grille off and change out the sensor.

 

with above on how to test it.

I thought mine was broke on by daily driver as the lights were on iin the morning and it was sunny. I just happened to be taking it into the dealer for another waranty repair and was going to mention the sensor, Well wouldn't you know it the lights turned off right before I turned into their driveway.

 

Whatever is happening, the air-conditioning controls have nothing to do with the headlight auto on.

 

So I did this and at first nothing happened. I used a yellow light headlight. Maybe I didn't hold it long enough. Swapped to a LED flashlight and at first nothing. Until I actually pretty much had to lay the flashlight on the sensor. At this point, it still took like 20 secs or so for the lights to shut off.

After that, I was able to get them to shut off from slightly far away from the sensor. Will try tomorrow and see what happens. Maybe the sensor went our of whack? It's happened before but it never took this long nor did I have to put a flashlight to it. Maybe it is starting to fail??

 

The light sensor also has the sensor for the AC auto mode. It's all in the same sensor. The AC auto mode also has another sensor in the front bumper.

 

Explain, please.

 

Read the owners manual in the section dedicated to the AC. I don't know exactly how it works since I never used the auto mode for the AC. But it is mentioned there, that there is a sensor that is part of the auto mode for the AC that is located in the same sensor as the auto light sensor. Section 4. Don't remember what page.

 

anyone has an idea on what's happening with my sensor?

 

It does have a time delay. So it doesn't keep turning them on and off at the dawn/dusk times or going under a bridge, etc.

They usually turn on when I start it in the garage and it takes usually 20 seconds or so to turn off once I pull out into the driveway.

 

My headlights also take about 30 seconds to shut off after I've backed out of the dark garage into the sunlight.

Lisa- the sensor in the dash is referred to as a "sunload sensor" in the Service Manual and shows that it is used for both the lighting and the HVAC.

The sensor in the front bumper area is for outside air temp.

 

Well this morning it happened again. It was 8am, sun was rising but it was already out and lots of daylight. The lights never shut off. I put my LED flashlight on my phone on the sensor and they shut off. Removed the flashlight, and 15 secs later, the lightswere backed on. If would it be possible the sensor is not working too properly/about to die/ sensitivity is starting to fail? I'll try to go for a ride around 12 or 1pm today and see what happens

 

Does it only happen when the sun is rising/setting? Mine does the same thing when the sun is low. I've just learned to live with it. I never have any issues other than during sunrise.

 

Is your windshield tinted?

Could be as simple as a failing sensor. Electronic gremlins are always a PITA.

Wish I had a more helpfull answer for you.

 

Yep, the daylight sensor is just that little bubble on the dash in the center speaker grill cover.

It works by sending a voltage reading to the BCM (via the HVAC) of the amount of day light it is seeing.

So when you start the car, the lights will come on, and after few mins for the BCM to see daylight long enough from the sensor (voltage in from the sensor constant long enough), then the BCM will kick off the lights.

On the other side of the coin, all it takes is a quick change in the voltage of the sensor so the car thinks that it in dusk lighting for just a brief second, and the BCM will kick the light on instead.

So BCM is quick to turn the lights on and keep them on like if you are going through a tunnel, but slow to turn the lights off instead (after you come out of the tunnel instead).

So being that the sensor is not throwing a code, it's putting out a voltage to begin with, either the sensor diode is starting to fail, the bubble on the sensor is clouding, or you have a problem in the wiring or BCM instead.

So on that note, with the center grill pulled, sensor pulled out of the speaker cover, it's pretty easy to clean the dome bubble, and just a touch of Brasso and cloth with clean any cloudiness of the sensor dome so the inner sensor can pick up the correct amount of light so the resistance from the sensor if correct for the lighting conditions.

Or, since you have the sensor in hand already, a replacement Corvette Daytime Running Lights Ambient Light Sensor is only around $25 instead.


To add, keep in mind that the BCM is reading sensor Voltage value through the sensor wiring to the BCM, so although you might think that the problem is with the sensor itself, it may be in the wire connections from the sensor to the BCM the problem instead (or even the BCM).

So the long way repair is to first test the sensor in both bright light and dark light conditions for its Resistance reading to begin with, and if the sensor checks out, then you know the problem is either in the wires or BCM instead. As for the quick way to determine such, a Tech II will give the reading at the BCM level and easy to check that against the actual sensor voltage level per lighting condition. If the two are not close to being the same, then wiring or HVAC/BCM problem instead.

 

If I remember correctly, if the AC is on "Auto" the screen will only show the outside temperature. If you click the **** to change the inside temp, then it will also show the inside setting for a short time.

I think so anyways. I don't use the "Auto" function very much. What was your temp set at? 60? I didn't think it went that low.

 

It actually is tinted with 50% percent.

So today I drove the car at around 2pm until 3pm and it was sunny out. The senso works perfectly under this conditions. Parked for an hr and got back in at 4pm and then the sensor thinks its dark.

At this point I'm guessing it might be the tint interfering with it. But I mean the difference from 2pm to 4pm isn't much in sunlight.. Anyway to adjust the sensitivity???... It really irritates me and then my running lights don't work cuz when I override the auto light then I have no lights at all..

 

You can always turn on the running/parking lights so you aren't completely 'dark', but it's not the same in the front when the brighter turn signals are switched on constantly in DRL mode.

Unfortunately there's no way to force the car to stay in DRL mode.

I don't know if you can re-calibrate the sensor/circuit. The "Scientist" Dano523 is one of the few who could possibly answer that.

And, this isn't the first time somebody has posted about a similar issue when they had a tinted windshield, which happens to be illegal in my state.

At least you don't have to tear into your car.

 

[quote]Daytime Running Lamps (DRL)
The daytime running lamps (DRL) will illuminate the right and left front turn signal bulbs continuously. The DRLs will operate when the following conditions are met:

The ignition is in the RUN or CRANK position
The shift lever is out of the PARK position for vehicles equipped with automatic transmissions or the parking brake is released for vehicles with manual transmissions.
The high and low beam headlamps are OFF.



The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between .2 and 4.9 volts depending on outside lighting conditions. The HVAC control module provides a low reference ground and a 5-volt reference signal to the ambient light sensor. The HVAC control module monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control (ALC) when the headlamp switch is in the AUTO position. The HVAC control module sends a signal to the body control module (BCM) via class 2 serial data commanding the BCM to turn the front turn lamps on steady (non-flashing). Any function or condition that turns on the headlamps will cancel the DRL operation. With the turn signal/multifunction switch in the OFF position, the turn signal lamps will either be turned ON or OFF after a 30-second delay, depending on whether daylight or low light conditions are sensed by the ambient light sensor.[quote]





So the easy way to solve the tinted windshield problem with less light to the ambient sensor now, voltage regulator from the sensor input voltage wire, and jump past the sensor to connect the voltage regulator output back to the sensor output wire to gain back the needed sensor output voltage difference to compensate for the tint difference between the BCM night and day setting now. With out knowing the difference now of the sensors output voltage, would take a stab that is something like just a .5 voltage that would need to be added back in to the sensor output voltage to make the needed difference.

Or take the car into the dealer to be reprogrammed for the difference in the sensor reading due to the tinted windshield instead.

 

the sensor used for the headlights is also used for the climate control system, for e.g., the car is monitoring the interior temperature but if it is sunny outside it will boost the air flow when the air conditioning is on to compensate for the sun