Why Do I Have Two?

DSN46 · October 1, 2008

Hi there,

I am currently trying to disable my "auto headlamp" feature on my 02 Tahoe.

I have read until my eyes bled about how to do it different ways. I am trying to stick a 1.5kohm resistor into the plug of the light sensor to fool the BCM into thinking that it is daylight all the time. All went well until I noticed I have TWO little black domes on my dash. One just to the right of center and one to the left of center up in the defrost area.

Now, which one is the light sensor? And what would the OTHER one be for?

I have searched and even called the dealer and they can't tell me what they are both for (amazing really).... They say it only calls for ONE part.

Please let me know if you have any idea as to which one is the light sensor and what the other one is about.

Thank you!

James

jrrod2004 · October 1, 2008

Hi there,

I am currently trying to disable my "auto headlamp" feature on my 02 Tahoe.

I have read until my eyes bled about how to do it different ways. I am trying to stick a 1.5kohm resistor into the plug of the light sensor to fool the BCM into thinking that it is daylight all the time. All went well until I noticed I have TWO little black domes on my dash. One just to the right of center and one to the left of center up in the defrost area.

Now, which one is the light sensor? And what would the OTHER one be for?

I have searched and even called the dealer and they can't tell me what they are both for (amazing really).... They say it only calls for ONE part.

Please let me know if you have any idea as to which one is the light sensor and what the other one is about.

Thank you!

James

One is for the auto lamps, the other should be for the auto climate (if equipped). If not, then I dont know and someone here will correct my error

pwall · October 1, 2008

Hi there,

I am currently trying to disable my "auto headlamp" feature on my 02 Tahoe.

I have read until my eyes bled about how to do it different ways. I am trying to stick a 1.5kohm resistor into the plug of the light sensor to fool the BCM into thinking that it is daylight all the time. All went well until I noticed I have TWO little black domes on my dash. One just to the right of center and one to the left of center up in the defrost area.

Now, which one is the light sensor? And what would the OTHER one be for?

I have searched and even called the dealer and they can't tell me what they are both for (amazing really).... They say it only calls for ONE part.

Please let me know if you have any idea as to which one is the light sensor and what the other one is about.

Thank you!

James

The '02 should have seperate lights for the DRL, apart from the low/high beams.

Simply unplug the lights. ;)

DSN46 · October 1, 2008

Thanks for the replies!

M. Cueva hit the nail on the head! The driver's side sensor is a "sunload" sensor for the climate control. The passanger side is the "ambient light" sensor for the headlamps.

Once I told my parts guy about the sunload sensor, he knew where to look and told me which was which.

I'm a happy camper now!

Oh yeah, just in case someone else searches this thread, I was not looking to turn off DRL's. I am looking to disable the auto-headlights that come on at dusk.

Thanks again,

James

ryan_hermanutz · October 1, 2008

I may have a simple solution to your dilemma. Your emergency brake should control your automatic lights. If you push your brake down 1 - 2 clicks from the top, this will not engage your brake and this should disengage your auto lights.

4xBill · October 1, 2008

I wouldn't play around with the sensors, wouldn't want to damage them in any way. You should be able to overide the auto headlight feature by pressing the "dome overide" located below the headlight knob button 4 times. I know this is the procedure for a '02 Silvy. I can't imagine it being much different for the other full size models.

Zembonez · October 1, 2008

Silly question?

Why would you want to disable auto headlamps? I think it's one of the coolest features GM has come up with. I've never even turned my headlamp switch on in my truck...

Nick The Great · October 1, 2008

I wouldn't play around with the sensors, wouldn't want to damage them in any way. You should be able to overide the auto headlight feature by pressing the "dome overide" located below the headlight knob button 4 times. I know this is the procedure for a '02 Silvy. I can't imagine it being much different for the other full size models.

But he'd have to do that every time he starts the truck?

Silly question?

Why would you want to disable auto headlamps? I think it's one of the coolest features GM has come up with. I've never even turned my headlamp switch on in my truck...

Maybe he has control issues and doesn't like the truck having power over him. Maybe it's hard for him to steal gas at night with the damn headlights on!

The one time a year I didn't like it on my 99 was at Christmas time. There is a local farmer who puts up miles of Christmas lights. People come from miles around to see them. You just slowly cruise by at 2 or 3mph, with your lights off, so you don't blind the oncoming traffic. It sucked not being able to take the truck.

I think there should be a button to override autolamps much like the dom light button. Our GMT900's at least have that stupid springy dial which can turn the lights off.

pwall · October 1, 2008

<snip>
Oh yeah, just in case someone else searches this thread, I was not looking to turn off DRL's. I am looking to disable the auto-headlights that come on at dusk.

Thanks again,

James

Ah yes...sorry, mis-read your initial post.

DSN46 · October 1, 2008

I may have a simple solution to your dilemma. Your emergency brake should control your automatic lights. If you push your brake down 1 - 2 clicks from the top, this will not engage your brake and this should disengage your auto lights.

I knew about doing this, but I don't want the E-brake light on the dash showing up.

I wouldn't play around with the sensors, wouldn't want to damage them in any way. You should be able to overide the auto headlight feature by pressing the "dome overide" located below the headlight knob button 4 times. I know this is the procedure for a '02 Silvy. I can't imagine it being much different for the other full size models.

Yes, I could just tap the dome overide button 4 times, but I want it more "permanent" than that. As for the sensor, it is just a "resistor" in the line (albeit a photo-sensor resistor) that puts out a certain amount of voltage when the sun is shining on it. All I had to do was get a resistor from Radio Shack that matched the photo-sensor's output and it tricks the BCM into thinking it is always daylight.

Silly question?

Why would you want to disable auto headlamps? I think it's one of the coolest features GM has come up with. I've never even turned my headlamp switch on in my truck...

And finally... the question that gets to the heart of the matter. I knew Zembonez would cut to the chase!

It is a "control" thing with me as well as a "practical" one. I have long resented Auto manufacturers and their "mother-hening" us to death with everything from seat belt reminders to head-light chimes. I am a retired police officer, and the FIRST thing I always did when I was issued a new car every two years was to go through the "monkey dance" in the Crown Vic specified by the manufacturer to turn off ALL of the bells and whistles. (You can't very well have three guys hanging out of the doors while cruising slowly through alleys at night looking for drug deals to jump out on with "BONG, BONG, BONG" going on)

What can I say? I want to be able to turn my lights on and off at MY will, without pushing something 4 times, or leaving the parking brake on, etc.

At any rate, I pulled the right sensor. Pulled off the harness and stuck a 1.5k ohm resistor in it. Tested it in my garage and I now have complete control of my headlight situation. Im happy.

Thanks again for all the replies. Once again, you knowledgable folks on this forum have headed me in the right direction to fix something, and it worked!

James

Zembonez · October 1, 2008

What can I say? I want to be able to turn my lights on and off at MY will, without pushing something 4 times, or leaving the parking brake on, etc.

Good answer James. I'll have to agree with you on all of the damn warning chimes for this and that. I also get tired of them. Personally I am a fan of the auto headlamps and wish I had the option on my other vehicles, but I am glad your "fix" solved it for you.

JIM.

superjim · October 1, 2008

Maybe it's hard for him to steal gas at night with the damn headlights on!

Don't know about stealing gas... but it sure is hard to spotlight deer with the headlights on.

DSN46 · October 2, 2008

Maybe it's hard for him to steal gas at night with the damn headlights on!

Don't know about stealing gas... but it sure is hard to spotlight deer with the headlights on.

LOL

I wish I could find a deer that wasn't only 3 feet tall! Since we moved down here to Florida 9 months ago, I haven't seen any deer worth hunting.... or alligators for that matter...

I do miss my Missouri

James

minibike132 · October 2, 2008

Maybe it's hard for him to steal gas at night with the damn headlights on!

Don't know about stealing gas... but it sure is hard to spotlight deer with the headlights on.

LOL

I wish I could find a deer that wasn't only 3 feet tall! Since we moved down here to Florida 9 months ago, I haven't seen any deer worth hunting.... or alligators for that matter...

I do miss my Missouri

James

Get someone to take you on a boar hunt, if you are used to white tail hunting alligator isn't going to do it for you. Alligators are pretty dumb it's not a great hunt.

DSN46 · October 2, 2008

Good idea!

Never been boar hunting. Have a friend who did it with a bow.. said it was pretty intense since it was a pretty damn big boar (pictures showed him kneeling next to it).

I am told that they grow quite big near southern Georgia/northern Florida.

I wasn't really planning on an alligator hunt... I just haven't seen any yet that impress with their size. Usually the little ones that hang out near waters edge close to paths and such.

Thanks,

James