Guide Matic

[SK903]

I know that the 1964 models had the guide matic concealed above the headlights. here was it located on future models and was it ever discontinued?

[Glen]

From the inception the sensor was on top of the dash.  I don’t know when the change was made but 1961 the sensor was also on top of the dash.  The slim ones shown in the pictures here: https://goo.gl/8Fgg21 was preceded by a much fatter one. 
Also the early system was called Autronic Eye.

[V63]

It was tucked behind the grill in following years (1965 up) . It was dropped in the late 80's ? It reappeared sometime later and I had it on an 06 DTS. I had a loaded STS 1997...don't think it had it?

It works 'better' on the DTS...but with traffic any more, you seldom get the chance to use your brights anymore.

[Walter Youshock]

1953 through 1959 was Autronic  Eye.  1959 was unique in that it was the only Autronic eye with a sensitivity control.  It was the first year the eye was on the center of the dash.

1960 introduced Guide Matic.  1964, the eye was in the fender.  1965 it was behind the grille.  1987 was the last of the original option. 

[D.Smith]

Funny how that option came back and was renamed  "Intelibeam".  Everything old is new again.  The sensor is now up on top of the inside of the windshield.     My 2007 DTS didn't have the option, but my former 2009 and current 2011 Chryslers have it (called Smartbeam) and it works great.   Far more reactive than the old Guidematic systems.  Maybe the higher location of the sensor is better?   Faster electronics?     Anyone here have experience with the newer system in todays Cadillacs?     

My 1961 has Guidematic  although it is only referred to as "Power headlamp control" that year.    I leave it off as it is very erratic.    I've had many 70s Cadillacs with it and they only seemed to work really well on roads without street lamps.

[Walter Youshock]

My aunt and uncle's '76 Lincoln had it and it was so touchy the lights would go into spasms when the moon was full. 

[67_Eldo]

The 1967 shop manual indicates that the photocell is located beneath the front speaker grille. If you have stereo front speakers, the photocell is beneath the left grille.

[Walter Youshock]

I believe that is for twilight sentinel, not auto dim.

[SK903]

Thank you all for your replies.

[Eric DeVirgilis CLC# 8621]

Intellibeam first (re)appeared in 2005 model year. As Dave mentions, it's far more refined than the older Guidematic/Autronic Eye auto dimming systems of the past.

Photocells mounted on dash under speaker grilles are used for Twilight Sentinel which turns headlights on/off in response to outside lighting conditions and will also keep headlights on for a preset duration after the ignition is switched off. 

In case you're wondering about that too - 1964 was the first year for Twilight Sentinel and has remained a Cadilllac accessory ever since, although has become standard equipment for some time now.