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I never understand this..... what are they?

all I know is, they keep the headlights on for a time period that you choose (by the knob) so you can see while getting into your house.

Is that all? can someone explaint he reason/real use for them? Thanks
 

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The reason that you stated yourself is the real reason for the twiligt sentinal. It is a retrostat and just like you said, keeps the lights on for a set period of time. Also if you turn the knob all the way to the right, the dome lights will probably come on depending on the model.
 

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It stands guard to turn your lights on at dusk. Hense the name. It can be adjusted to turn them off after a period also. Plus when in the TS position the headlights come on w/the w/s wipers.
 

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Changing the system from Daytime Running Lights (DRL) to regular headlamps when the wipers are activated is a feature that was added around 1997, and may or may not be present depending on options.
 

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rayzer said:
Changing the system from Daytime Running Lights (DRL) to regular headlamps when the wipers are activated is a feature that was added around 1997, and may or may not be present depending on options.
That's probablly true. From experience I know the 80's and early to mid 90's where only light sensative.

Here's a question that's sort of along the same lines. What about the Optical Eye found in the late 50's and 60's models? Does it work along the same princaple or does it just turn from high to low beam?
 

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Scrapyard,

I've never worked on one of these, but here's the best information I can get

In 1952, the Autronic Eye, an automatic car headlamp beam control was introduced to the public by General Motors. A phototube atop the left end of the dashboard, just inside the windshield, dimmed the lights upon the approach of an oncoming car, and back to bright when the traffic had passed. It was offered on Oldsmobile and Cadillac cars. But automatic headlights tended to flicker erratically in response to minute fluctuations of light. In 1959, the name became the "Guide-Matic Power Headlight Control." General Motors had solved the problem with a new gadget: "With a twist of the dial autronic-eye lets you control the automatic dimming of your lights." Thus the driver could manually control an automatic device designed to eliminate the need for manual control.

I know that around 1960, for one year there was a version of the system that did something, not sure what, that indicated to on-coming drivers that the vehicle was equipped with Guide-Matic. Whatever it did, in this year there were a lot of problems, and dealers ended up disconnecting many of the systems.
 

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I'm a little late responding but you are talking about 2 of my favorite features! The Twilight Sentinel is a fully automatic headlamp system. When it gets dark enough outside (at *twilight*), the system will turn on all of your headlamps and taillamps automatically without you having to do anything. The opposite is true as well--when it gets light enough outside (at *dawn*) the system will turn off your headlamp system until it gets dark enough again outside. You should never have to touch your headlamp switch other than foggy, bad weather days or if you're attending a funeral. A second feature of the Twilight Sentinel is that it will keep your headlamps on for a preset time period to illuminate your path to safety in darkness. When you move the rheostat control right past the "OFF" position, the headlamps will remain on for about 3 seconds and then go off. The further you move the control away from "OFF," the longer the headlamps will remain on up to a maximum of about 3 minutes on some vehicles. Starting in 1996, the system was incorporated with the Daytime Running Lamps so during the day the DRL's were active and when the Twilight Sentinel turned on the headlamp system, it turned off the DRL's. This feature came out in 1964 and has always been my favorite feature.

As for the Guidematic: Auto Dimming, the feature was first available on the 1954 models and was available through the 1988 models. It was pretty cool because if you were driving in the country and had your high beams on and there was a vehicle approaching you, the system would switch to lo beams automatically and when the car passed, would return to high beams. The was a light sensitive photocell that would sense an absence of light and would turn the high beams on. When it detected light, it would switch to the lo beams automatically. There was a sensitivity control that allowed the driver to control the sensitivity of the photocell to allow dimming to occur with more or less light.

Max
 

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I didn't think the twilight sentinel turned the lights on when it gets dark, I thought that's what the little sensor on the dash is for. There are two on my dash, 1 for auto climate adjustment and the other to turn on or off the lights. Not to nit-pick, but I thought the twilight feature was ONLY for headlights on delay after shutoff to get safely into your house or ?.
 

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Ralph--Kempie is right. The main function of the Twilight Sentinel is to operate your headlamp system automatically. The delay mode is an additional function of the Twilight Sentinel. The photocell on your dash is the sensor for the Twilight Sentinel to determine the ambient light and operate the system appropriately. Try turning off your Twilight Sentinel. You will have no automatic operation of your headlamp system and will have to turn your headlamps on manually. If you move the control knob right past the off position, the headlamps will operate automatically and will turn off within seconds of turning off the ignition. Again, the further you move the control from off, the longer the headlamps will stay on when you turn off the ignition up to a maximum of 1 1/2 - 3 minutes.

The other sensor that you mention on your dash does help control the climate control. It is called a sunload sensor and measures the intensity of the sun and can compensate the climate control on bright sunny days or cloudy humid days.

Max
 

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Maximln said:
Ralph--Kempie is right. The main function of the Twilight Sentinel is to operate your headlamp system automatically. The delay mode is an additional function of the Twilight Sentinel. The photocell on your dash is the sensor for the Twilight Sentinel to determine the ambient light and operate the system appropriately. Try turning off your Twilight Sentinel. You will have no automatic operation of your headlamp system and will have to turn your headlamps on manually. If you move the control knob right past the off position, the headlamps will operate automatically and will turn off within seconds of turning off the ignition. Again, the further you move the control from off, the longer the headlamps will stay on when you turn off the ignition up to a maximum of 1 1/2 - 3 minutes.

The other sensor that you mention on your dash does help control the climate control. It is called a sunload sensor and measures the intensity of the sun and can compensate the climate control on bright sunny days or cloudy humid days.

You must be assuming I use the twilight sentinel? It is always in the off position and I still get auto lights come on. I park in a dark parkade and all the lights come on, including the dash and radio/climate controls, and it is always in the "off" position, just to clarify, so I hope mine is working properly.

Max
:confused:
 

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The true purpose of the "Twillight Sentinal" is the same as it is on every other vehicle with this feature.. SECURITY. Your wife comes home late at night after hanging out with the girls (allegedlly) and parks the car in the driveway and gets out to walk up to the front door of the house, the twillight sentinal can be set to stay on for as long as it takes her to normally get inside.

So it shines the lights on the area she is pointing the car towards. That is all it is for. If you notice the knob allows you to adjust the length of time the lights stay on. That is what its for, nothing else. This feature was also on my Jeep Grand Cherokee Ltd. It does not control the daytime running lights or the sensitivity of when the headlights turn on.
 

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mnymaker said:
The true purpose of the "Twillight Sentinal" is the same as it is on every other vehicle with this feature.. SECURITY. Your wife comes home late at night after hanging out with the girls (allegedlly) and parks the car in the driveway and gets out to walk up to the front door of the house, the twillight sentinal can be set to stay on for as long as it takes her to normally get inside.

So it shines the lights on the area she is pointing the car towards. That is all it is for. If you notice the knob allows you to adjust the length of time the lights stay on. That is what its for, nothing else. This feature was also on my Jeep Grand Cherokee Ltd. It does not control the daytime running lights or the sensitivity of when the headlights turn on.
That's what I thought but I am not 100% certain.
 

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yeah i love the TS system, i was pulling into a parking garage at like 11am, and they turned right on, then went i left, the turn right off. its great, you'll never look like the dumbass with his lights off at 9pm :D
 

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Mnymaker--I don't know where you have been getting your information but it is incorrect. The primary function of the Twilight Sentinel is automatic control of your headlamp system and the secondary function is to delay the turn off time when you turn off the ignition. It has been this way since its introduction in 1964. Mnymaker, in your 99 STS (that's what you have listed as your automobile), move your Twilight Sentinel lever to the "OFF" position at night. You will get a message that reads "HEADLAMPS SUGGESTED" because you have turned off the automatic control for the headlamps but the system still "thinks" that you need to have them on. Only the 98 and up Sevilles and the 00 and up Devilles do this. For all other Cadillacs with the Twilight Sentinel control, if you turn the system off, there will be NO automatic control of the headlamp system and you will have to operate them manually.

The Twilight Sentinel system (automatic control of the headlamps and the delay feature) is only on the higher end GM cars where you have an on/off feature for the automatic operation of the system and a rheostat control incorporated for the delay time. I think all other GM vehicles now have automatic control of the headlamps which are also incorporated with Daytime Running Lights but there is no delay feature. Some models, through special programming, have a delay feature that can be changed from 0 second delay, 15 second delay, 30 second delay, etc. but not as easily as the Twilight Sentinel control.

There was (and maybe still is) a delay feature on the Jeeps (a friend of mine also had one) but that is all it is--a delay feature. It is NOT the Twilight Sentinel control and does not have any automatic control over the headlamp system.

If you read in any owner's manual or service manual, the description of the Twilight Sentinel begins with the automatic control of the headlamp system and then goes on to describe the delay feature.

Max
 

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While Cadillac does call the automatic headlights twilight sentinel, other GM brands that have auto headlights that dont have a delay feature are not called that.

This is from oldsmobile.com and describes my wifes Alero:

Automatic Lamp Control
Your headlamps and other exterior lamps will come on automatically, whenever and wherever light is limited. You may never need to touch the lamp switch again

no mention of delay, because there isnt one, also no mention of twilight sentinel


This is from Cadillac.com and describes my SLS:

Lighting


Daytime running lamps with Twilight Sentinel automatic operation and wiper-activated automatic-on feature, tungsten-halogen headlamps with flash-to-pass feature, front cornering lamps, and illuminated entry system

In this case they call the whole system twilight sentinel. So it looks like GM only uses the twilight sentinel lingo with cars that have the delay, not all cars that have auto-on lights. Cars with auto-on lights have "automatic lamp control". But you are probably both right, auto companies have a way of using terms for different things, until it all becomes diluted.
 
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