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Everything you wanted to know about Photo Cells


davedog

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OK, I'm posting this information to hopefully help someone not spend as much time as I did with this tonight.

From a 1992 eldorado, may work on other models/years

PHOTO CELL REMOVAL:

This part is kind of vague in the manual....was to me anyway. All there is to it is remove the plastic grill by popping it out of the dash top with a flat blade screwdriver. Next remove the photo cell socket from the underside of the plastic grill (the photo cell is the one on the LEFT, the one that DOES NOT have a "dome-shape" on top) by twisting it. Next pull the Blue-colored plastic part out of the photo-cell socket (socket was orange on my car). That’s it! That SMALL TINY blue piece is the photo cell, and will set you back about $50! YOU DO NOT HAVE TO REOMVE THE DASH TOP TO REMOVE PHOTO-CELL...TRUST ME!! :P

HOW TO TEST PHOTO CELL:

Start car, or turn ignition to ON. With a volt-meter, test the voltage from pin A on the socket (with the photo cell OUT of course) - this will be the connector to the white wire - to a ground point. The voltage should be 5 volts. If it is not there is a short in the wiring circuit, if it does test 5 volts test the voltage from pin A to pin B on the photo cell socket - from the white to the black wire - this should also be 5 volts. If it is 5 volts, congratulations, you have a BAD PHOTO CELL, if not there is a short in the wiring circuit.

My cell DID test out BAD so I'm good to waste 50 bucks now.

NOW, if you saw my post in the thread about disabling DRL, I wanted to know if you could enable this on a car without it. Well, I discovered you can on my car....sort of :rolleyes:

Simply remove the photocell from the photo cell socket, and make sure the twilight sentinel is ON. That’s it! Now the lights will come on approx 10 seconds after you start the car, and they will shut off on their own, after some time, depending on how long you have it set to. So in other words, in the absence on the Photo cell the headlights go into "Night" mode. I have decided however, to replace the cell. :lol::lol:

hope this helps someone!

-dave B)

Crystal Red Tintcoat Exterior | Shale/Brownstone Interior | 32k

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This is good to know. Thanks a million for the post!!

If you really want to make people safe drivers again then simply remove all the safety features from cars. No more seat belts, ABS brakes, traction control, air bags or stability control. No more anything. You'll see how quickly people will slow down and once again learn to drive like "normal" humans.

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This is good to know. Thanks a million for the post!!

No problem, I will report back here when I get the new cell on Friday.

-dave B)

Crystal Red Tintcoat Exterior | Shale/Brownstone Interior | 32k

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As Promised, Results of New Photo-Cell:

-Ordered from Kelly, Cadillac of Chattanooga, TN on Tuesday, August 30th, 2005

-Order arrived at the dealer Thursday, September 1st, 2005

-Picked Up Today, Friday, September 2nd, 2005

-Photo Cell to automatically turn on headlights at night is GM Part # 914032

-Cost for part: $51.44, TN Tax $4.76, GRAND TOTAL: $56.20

-I put the new sensor in while sitting in the dealer parking lot :lol: wasn't about to drive 25 minutes home and find out this $56 part (the size of about 5 nickles stacked on each other) wasn't going to work. Put hand over sensor, and started car....POOF! My lights turn on after only 10 seconds! :D Take hand off sensor, lights go back off after 10 seconds. Put hand back on sensor, and sure enough, lights come back on. At this point a decide it is fixed, look around to make sure no one had been watching like I was crazy or something, and drove home. :lol:

WAS IT WORTH IT?

Eh, probably not, but I feel better now that they are working right, and I was already so far into this project, I figured, eh it's only $50 bucks.

Sorry, to be so detailed, but upon searching the archives I discoved there was almost nothing about replacement, diags, etc, on this part, so I'm just trying to help someone out down the road.

Oh, and if anyone needs a picture of the photo cell, PM me with your email, and I'll send you one.

-dave B)

Crystal Red Tintcoat Exterior | Shale/Brownstone Interior | 32k

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Can you connect the old cell to a microampermeter and see if it works? I still believe the problem is not the photocell itself since there is nothing in it to degrade but rather the contacts, conduits etc. A cilica photocell may be exposed to direct sun light for decades with no visible degradation. You have several of them in your $5 calculator BTW... <_>

The saddest thing in life is wasted talent

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I'm no photocell expert, but I don't see how it could be the contacts themselves, it almost has to be in the photocell itself. Judge for yourself, here is a pic with several views of the OLD BAD photocell, the new one looked NO DIFFERENT, contacts the same shapes and condition.....I dunno :unsure:

photocell.jpg

-dave B)

Crystal Red Tintcoat Exterior | Shale/Brownstone Interior | 32k

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Well... I do not know either. The only custom piece is the blue plastic housing. It makes sense to replace the photodiode itself (a couple of bucks). Can you remove the old one to see the part number. It might be on sale on ebay for $20 for 100 pieces. ;)

Actually you know what? The plastic cover could degrade over the years and chanfe the transmittance...and the cell itself still be fine. If you could remove the both old and new cells from the housings and make some comparison tests it would end this discussion.

The saddest thing in life is wasted talent

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Cadmium sulfide photocells will drift in resistance values over time. That is most likely what happened to Dave's car. I would defintely say the old sensor was bad as a new one cured the problem.

Where are cadmuim sulfide photocells used in a calculator???

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Well... I do not know either. The only custom piece is the blue plastic housing. It makes sense to replace the photodiode itself (a couple of bucks). Can you remove the old one to see the part number. It might be on sale on ebay for $20 for 100 pieces. ;)

Actually you know what? The plastic cover could degrade over the years and chanfe the transmittance...and the cell itself still be fine. If you could remove the both old and new cells from the housings and make some comparison tests it would end this discussion.

WAY ahead of ya. :lol: Pulled the photo cell out of the housing the other night, ran the numbers through several search engines online, ebay, ect. That piece is probably only worth about $0.20 if you could find it. NO matches for those numbers ANYWHERE> Kinda strange...

They are making KILLER profit on these things...

-dave B)

Crystal Red Tintcoat Exterior | Shale/Brownstone Interior | 32k

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Cadmium sulfide photocells will drift in resistance values over time.  That is most likely what happened to Dave's car.  I would defintely say the old sensor was bad as a new one cured the problem.

Where are cadmuim sulfide photocells used in a calculator???

Well... this explains a lot! CdS photocells are not as durable as silicon ones. WTH they used them? Cost? Spectral range? (the pick of sensitivity of silicon cells is in near IR versus CdS's in visible, but it is still has plenty of sensitivity in visible range)...Or maybe a possibility to charge davedog another $50 in a few years? :D

The saddest thing in life is wasted talent

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...Or maybe a possibility to charge davedog another $50 in a few years? :D

Yeah, I believe that would be the reason! <_>

Hopefully though, if this car lasts another 78k, I will have moved onto something "bigger and better" :P

-dave B)

Crystal Red Tintcoat Exterior | Shale/Brownstone Interior | 32k

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...Or maybe a possibility to charge davedog another $50 in a few years? :D

Yeah, I believe that would be the reason! <_>

Hopefully though, if this car lasts another 78k, I will have moved onto something "bigger and better" :P

-dave B)

Hopefully... how's your coolant level BTW?

The saddest thing in life is wasted talent

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Thanks for asking! :D

Just checked, it is perfect. It ought to be for how much I $$$ I put into it a few weeks ago. The new water pump did the trick!

-dave B)

P.S. adallak, there is a newbie on the board somewhere complimenting me on my "Black" eldorado....could he be your brother? :lol::lol::lol:

Crystal Red Tintcoat Exterior | Shale/Brownstone Interior | 32k

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Thanks for asking! :D

Just checked, it is perfect. It ought to be for how much I $$$ I put into it a few weeks ago. The new water pump did the trick!

-dave B)

P.S. adallak, there is a newbie on the board somewhere complimenting me on my "Black" eldorado....could he be your brother? :lol::lol::lol:

I do not have a sister and do not think my brother ever visited this site. ;) If the person you mentioned is SHE I would like to know her better, at least she has correct colour perception!

:lol:

BTW, there did you get these nice green tires? :blink:

The saddest thing in life is wasted talent

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Does anyone not like twilight sentinel? I don't use mine, particularily because I like to be in control of my lights. I would definately use it if it automatically turned off the high beams if they were on. For instance, If I turn my lights off with my high beams on after pulling into my driveway and the next day is a cloudy day causing the lights to turn on than I am driving around blinding everyone because it is light out and I can't see the darn high beam indicator. Just a thought, probably very anal but I don't like that it will turn your lights on with the highbeams and not alert you. I'm sure they must have changed this on later models? Anyone know?

Chris

Christopher Petro

94 sts

67 coupe de Ville

user posted image

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Did you try here?

The trick is to get the specs to find a suitable replacement (preferably by measuring the new one for resistance, etc.) ......they can do some funny things with part numbers for 900% profit!

http://www.newark.com/

Never underestimate the amount of a persons greed.

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Dave:

Can you take some resistance measurements on the old cell?? Or if you don't care to mess with it you could mail it to me, maybe?

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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