1964 Twilight Sentinel Photoresistor Wanted

[Eldorado_64]

I think I need a new or good condition used photoresistor for the dash mounted photo cell of the Cadillac Twilight Sentinel. Any of you guys or gells have one for reasonable sale or trade?

I am also interested in hearing from any members w/ a more in dept know how of the workings of these classic Cadilac electronics? I'm open to modding it to work or perform better. I know I can get new photoresistors but not sure if the values will match and if I can get it to fit in same spot.

Who if any has completely rebuilt a full working "Guide" system such as the Guide-Matic Headlight and or Twilight Sentinel?

Thankx in advance,
Brandon J. of CA

[Bastian Hermeling]

Hi,

I´ve got a Deville from 1963. I bought it with two extra options missing. Power door lock, and the guide matic.
I bought the guide matic system from John Oldenburg as a complete system for about 270$. Top quality. Everything like new and it works great.
You can have look at the system at my fotopage. www.flickr.com search for "cadillac.maike"
And here is the mail adress from John: olden@yousq.net
He should have all the parts you need.
Best regards Bastian

[Glen]

I installed the Twilight Sentinel on my 68 ELDO.  I’ve never had any problems with it.  At one time I drew up schematics for the amplifier. 

What kind of problems are you having with your unit?

Glen

[Eldorado_64]

I installed the Twilight Sentinel on my 68 ELDO.  I’ve never had any problems with it.  At one time I drew up schematics for the amplifier. 

What kind of problems are you having with your unit?

Glen

I'm experiencing loss of sensitivity to daylight while in automiatic mode. As I stated above, the photo sell lens tissue over the actual photoresister has cracked open and a piece flew out when top was down (by this time I had completely removed top cap to insure it got cunlight to keep lights off in daytime driving). I can pull photoresister out but what should average resistance value be in full CA sun at high noon v/s a city night scene?

[Doug Houston]

Got names mixed up. I'm reading twilight sentinel, and writing Autronic eye. My apologies.

[Glen]

The unit I have is a later model.  As I recall the ’64 has a dome on top of the dash that the photocell sits in.  I don’t have the resistance values right now, I will have to find my spare and measure it.  Even then I’m not sure if they are the same.  The ‘74 parts book does not list the photocell for the ’64 cars. 

I did see the cover for the photocell listed and it is listed as “cover, late, early adjustment.” It seems to me the cover is the sensitivity adjustment.  But the absence of the cover would make it too sensitive and your problem is it is not sensitive enough.  I wonder if it is getting burned out by the constant full exposure to the sun. 

Just thinking out loud.

Glen

[Eldorado_64]

At what point did they stop using the adjustment to the lens cap (moving to block or let in light) opposed to actually utilizing a variable resistance dial (adjustable switch on dash and cell elsewhere such as in back of mirror) along w/ the fixed exposed photocell / photoresiter? Can I mod it as such? Place a photoresister open to daylight and use a reostat to adjust sensitivity of when lights turn on or off. I remember it was improved by '68, how different are the parts for that year such as the AUTO/OFF and time delay switch? Can it be fittted into case of the '64?

[Glen]

Looking at the parts manual the Twilight Sentinel on the ’64 was a one year only except it was also used on the ’65 series 75. 

I am having trouble finding any ’64 parts that are used in the ’65 and later cars.  It’s my guess you would have to transplant a complete system into the ’64.  On my ’68 ELDO the wiring harness for the Twilight Sentinel is a part of the main harness and not a separate harness which complicates things. 

I’ll see if I can dig out the spare photocell to get some measurements this weekend. 

Glen

[Eldorado_64]

I dont mind the wiring transplanting as long as I can get a wiring diagram for the car it cam from. My harness is completely in tact. Only the photoresister is going bad or already bad. It is exposed, meaning the thin plastic lens tissue that covers the internal cell is cracked open (not to confuse with the cap lens on the dial). Did '68 still use the blockinf/unblocking photorisiter to adjust or was it now a reostat switch?

[Glen]

No, the photo resistor is mounted behind a small plastic grill flush with the top of the dash pad.  Sensitivity and time delay is controlled by a variable resistor controlled by a knob behind the headlight switch knob. 

Glen

[Eldorado_64]

I might bewilling or needing to convert if I don't get the photocell for my original soon. Can I see some photos (pix) of the parts iused for '68, like th edash sensor, grill, the Twilight Sentinel box w/ switch. A diagram of shop diagram would be great if somebody can share to email in clear detail digital scan.

I was thinking I could hide the new photorister inside the defroster duct or in speake grill front edge and gut the original dash cap to act as a contol to a reostat underneeth. I'd like to utilize my od box as I did re cap it years back and looks good so far. Does anybody know for sure what pot resister if any in the Guide box controls the fixed sensitivity to the cell?
fleetwood60s1964@msn.com

Thank you.