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2001 Cadillac Eldorado ETC
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Discussion Starter #1
1. Does anyone know - if the RainSense wipers are on, meaning I have set the wiper switch to automatically sensing rain on the windshield, do the headlights come on? They do on my 2006 STS, but my manual for the 2001 Eldorado does not mention this.

2. Yesterday, late in the afternoon, while on the interstate, the sky was very dark and cloudy and other cars had their lights on, but my Eldo automatic headlights did not come on - the twilight sensor is new and does work. So I turned on the fog lights and saw that the headlight on indicator was lit, but the dash lights were not on. If I pulled the headlight switch out the dash lights would come on, but if the pull switch was pushed in the headlights stayed on (because of the fog lights), but the dash lights went dark. Anyone have an idea what is happening here?
 

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99 STS, White Diamond
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792 Posts
My owner's manual (99 Seville) clearly states that the low beams come on when the Rainsense is turned on. My bet is that if the manual doesn't say it does, it doesn't.

You say a "pull switch" for the headlights. That sounds like a conventional headlight circuit under direct control of the switch. In the Seville and later Cadillac models, the headlights are under the control of a computer so they can be turned on by things other than the headlight switch. Are you certain the the low beams were actually on with just the fog lamps on? Perhaps a shared dash indicator. (There are separate indicators in the Seville.)
 

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1997 Seville STS, 2000 Seville STS
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The headlights do come on when the fog lights are turned on, its a hard wired interlock, the fog light relay picks up the lowbeam relay to turn on the headlights. The dash illumination (and the rear tail lamps) remain under control of the twilight sentinel unless you actually turn the headlights on with the switch, so they will turn on and off based on the outside ambient light levels.
 

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2001 Cadillac Eldorado ETC
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Discussion Starter #4
Thanks for the responses. Very interesting and different from 2006 STS. I will experiment further this weekend.
 

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1997 Cadillac STS (BOSE w/AUX In, Massage Seats, URPAS, "Z")
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1. I was not aware of the FOG interlock part MarkC mentioned, I assume is right (he is always right) so I am not going to check the schematics.
2. 20 seconds after turning the wipers to ANY position (but OFF) the headlamps should turn ON (PZM will override the light sensor);
3. If the sliding switch is ON (i.e just slightly moved from the far left position past the click) then your headlamps are controlled based on the light sensor (but remember, the light sensor can be overwritten at any moment by the 20 seconds timer initiated in the moment the wipers are switched ON as described on 2). Now considering 2, I don't know if the headlamps are turned on by the 20 seconds wipers turn on timer even with the headlamp sliding switch (refereed as twilight sentinel switch) OFF, or just "Headlamp suggested" message is displayed on the IPC. I can not test it now as I am about 10K miles away from my car (South Africa), I will check when I am back in few weeks.
4. If the sliding switch is OFF then when the sensor indicates the lamps should be ON the "Headlamp suggested" message is shown on the IPC.

There is no difference (other than the shape of the controls) between a '92-'97 Seville, '94-'99 Deville, '92-'02 Eldorado AND a '98-03 Seville or '00-'04 Deville. In fact are even positioned similarly.

So from what you described above (I am not familiar with the '06 model) it seem to be quite similar (to identical) starting since '92.
 

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2001 Cadillac Eldorado ETC
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913 Posts
Discussion Starter #6
I wanted to complete this thread and bring it up to correct data.

I tested the headlight system today. In the dark the twilight sentinal turns on the headlights, tail lights, and dash lights, the same as if I pull the knob on the switch panel. In the sunlight the lights go out. If I turn on the fog lights, the headlights go on, even in the daylight. Turn off the fogs and the headlights go out. Turn on the fog lights, and hit the high beams the fogs go out. Lower the beam an fogs return.

Wipers - set the control to Auto and in 20 seconds the headlight system (headlights, tail lights, and dash) comes on. Wipers off, headlights off.

Know we know.:thumbsup:
 

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1997 Cadillac STS
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54 Posts
or you could just cover the twilight sensor as i have.... and headlights are always on..... HIDs at that
 
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