Write-Up: Replacing Twilight Sentinel Photo Cell

I want to change the sentinal sensor which controls my headlights turning on at dusk. My question is what is the proper way to remove the vent grill on top of the dash?

If you are going to keep the car any length of time and work on it yourself... please get a manual if you can. Usually can find on Ebay for $50 or less the set, nowadays.

That said -- If you search you will find instructions for talking the dash apart elsewhere on this site. There are some snap in fasteners under the dash pad, and screws on each end.

Seeing as how I was given my 91' Riv with no manuals, what does the twilight switch below the panel light dimmer do?

If it's the slider, it should control how long the lights stay on after you shut the car off at night. People who set it to max generally are trying to get themselves to the front door and find their house keys before the lights turn off... Other than that it's all up to your preferences.

Cool, thanks!

Anyone know the photo cell part number for the twilight sentinel (97 Riv)? I've searched through my Service Manuals and can't seem to find it listed. Checked out Ed Morad, AC Delco part suppliers, ebay, etc. with no luck. I would appreciate any suggestions. Thanks!

Derek,
Do you know if the 2 Sunload Temp Sensors, that you replaced recently, tie into the twilight sentinel at all.?
Those are the only sensors other than the single Ambient Temp Sensor that are in the forward dash panel.
Or does the sensor in the Rear View mirror have something to do with the twilight sentinel.?

I can't seem to find the info either.

Rivlanta wrote:

Anyone know the photo cell part number for the twilight sentinel (97 Riv)? I've searched through my Service Manuals and can't seem to find it listed. Checked out Ed Morad, AC Delco part suppliers, ebay, etc. with no luck. I would appreciate any suggestions. Thanks!

The P/N is 914032. I confirmed it also. It's $40 (www.monsterpartsonline.com)

Do you know where on the vehicle the sensor is installed.

it's in GMPD as 'sentinel sensor' their price $34.53, their number 914032 (yes it's 6 digits), with shipping $50.48. Monster shows it for $38.18, also shows picture. Sensor plugs into same harness as the HVAC sunlight sensor. I did not check the price with shipping from Monsterpartsonline.com; the 914032 number works on Monster and brings up the correct part.

Not sure why you could not find it but I have my suspicions:

1) it's not a Ford (Ford puts P/Ns in the service manuals, I don't know who else does
2) you asked others (Morad, Delco, eBay) who have no reason to know the # in the first place
3) you are not aware of how to make GMPD cough up part numbers. What you do is: do the search for the part; when you find it then put it in the cart, then proceed to check out. GMPD actually moves the items to *another* cart and shows the part numbers. You can then see the PNs before you commit to buy.

hope this helps

Albertj

PS: Hi RIck - the sensor is in the upper dishboard and looks like the sun sensor for the HVAC. The HVAC sensor is leftmost and the 'twilite sentinel" is to the right of it as you face front of car.

If you put the P/N 914032 into the lookup box on monster.com you can get to a drawing. The following does NOT work: On the home page put the P/N into the Search By Part Number box, select Buick on the dropdown list, then the parts will come up as listed but no drawings.

WHat works - To see drawings from the home page select the year make and model (say 1998 Buick Riviera) from the dropdown lists, When the catalog comes up THEN put the P/N into the lookup box on the top RIGHT side of the page. 2 listings will come up, one says 'headlight control' and has a View Illustration box in it. CLick that box, you'll get a picture with an index to the cutaway that tells you what's what.

Full wiring schematics as well, these are for a 96' but they should be the same...

http://brianesser.com/tech/96/LIGHTING/Twilight_Sentinel_Headlamps_1.JPG

http://brianesser.com/tech/96/LIGHTING/Twilight_Sentinel_Headlamps_2.JPG

http://brianesser.com/tech/96/LIGHTING/Lamp_Control_Module_Connector_Pinout.JPG

http://brianesser.com/tech/96/LIGHTING/Headlight_Switch_Pinout.JPG

Thanks for the Tip Albert.

U R Welcome, and a tip of the hat to Brian for posting the real nice drawing.

Albertj

What had me confused is my parts book shows the center sensor as "Ambient Temp Sensor" instead of "Ambient Light Sensor".
I need to make a correction to this listing I have.
Thanks for the pictures. I like pictures. At least the ones that are correct.

All those schematics and pictures are from Alldata.

Thanks to all...this is the information I needed!

I bought the sensor from Monster, and it seemed very difficult to change at first, then when I actually got the old sensor out I realized just how easy it was to change.

Basically you pull the sensor out through the top and plug the new one in. It's that easy. The hard part is grabbing the sensor to lift it out. The sensor itself is tiny, like changing a 194 light bulb - it just plugs in. If you pull the defrost grille up, you can twist and release the sensor holder, then pull the sensor out the top of it a little easier. There is no easy way to disconnect the wires like with the heat load sensors, and you don't want to.

I was surprised at how easily it went. Sorry I didn't take pics along the way.

Derek...thanks for the heads-up on this. Are you saying that it is possible to do the replacement without removing the defroster grill, but just a little harder to align the photocell into its socket? If I don't have to remove the defroster grill, I would rather not as my upper dash pad is brittle already from age and I suspect the defroster grill would be as well (I don't want it to crack).

You might. After doing it I thought you would be able to do it right from the top without pulling the grill. Give it a try. The hard part is getting any leverage with the windshield right above the sensor...

twilight sentinel
i just love that name. reminds me of my old avengers comics...off topic..sorry AA

Just finished replacing the twilight sentinel photocell on my 97 Riv and thought I would provide a few tips-and-pics for someone else that may need to do this:

1. The part number for the replacement photocell is 914032. (I purchased it from shopgmparts.com for $38.18 plus $9.95 shipping.)


2. To prevent tools and parts from accidentally disappearing down the defroster grill, cut two pieces of cardboard to fit around the front and sides of the photocell, making sure they fit all the way forward butting-up against the windshield.


3. With a small flat-tip screw driver placed just under the lip of the cell’s top hat, very gently and evenly pry-up the defective photocell from its socket. (When I did this, the photocell was so old and brittle that it cracked the top hat portion off and I had to use a sharp-pointed tool to pull what remained, out of the socket.)



4. Note the orientation of the exposed photocell socket terminals.


5. Using long needle-nose pliers, place the new photocell over the socket making sure the photocell terminals line up with the socket terminals. (The photocell is not polarity-sensitive and can go either way.)


6. Once the photocell is aligned in the socket, release it and press down on the top hat portion with your finger to make sure the photocell is fully seated.


7. If testing the twilight sentinel system during the day, place a piece of cardboard over the new photocell to fool it into thinking it is dark outside.

8. Start up your Riv, and with the interior headlight switch pushed-in (OFF), note the headlights, etc. and the interior instrument panel lights should come ON.


9. Remove the cardboard and note that very shortly your headlights and instrument panel lights go OFF.

10. Now have someone assist you by placing your Riv in NEUTRAL (or any gear other than PARK) and note that your headlights are OFF and your daytime running lamps (actually your bright headlights only) are ON.


11. Hopefully now your twilight sentinel system is as good as new. If it's still giving you problems, check the Lamp Control Module and/or instrument panel Headlight Switch.

Hope this helps!

Rivlanta wrote:

2. To prevent tools and parts from accidentally disappearing down the defroster grill, cut two pieces of cardboard to fit around the front and sides of the photocell, making sure they fit all the way forward butting-up against the windshield.

Now THAT is uncommonly common sense!

Great writeup, Craig, deserving of the coveted "Green Ribbon" (+)

New guy here. The Riv. is my wifes' ride, but I get to drive it now and then 'cause I get to maintain it. Lately (last 5-6 months) the headlights have been acting up. The lights would progressively take longer than normal to come on in the evening. Then, driving under lit up portions of the road they would shut off. The dash lights would remain on, but I would have to pull the light switch to get the headlights to come back on. Last Saturday, coming back from a trip, on a pitch black night, on a two lane hi-way, dodging deer, going around a curve, everything went black, headlights,and interior lights. Seemed like forever as I hit the brakes and went for the switch. Got lights back on while luckily staying on the road. My searching shows that it could be a few things, with the Light Contol Module being one possible place to look. Any suggestions, trouble-shooting ideas or any help woiuld be greatly appreciated! I am just glad that my wife wasn't behind the wheel.
Regards, Rick

Sounds like your Ambient Light sensor might be going (is) bad. It's that little bulb lookin thing in the middle of the dash pad. That lil guy is responsible for detecting proper lighting conditions for the Auto lights to go on and off; The LCM turns 'em on and off via that sensors' input.

Abaddon, if it is the culprit, what does the r&r entail?