Write-Up: Replacing Twilight Sentinel Photo Cell

Good to know. Great question and info! Are Ambient Light Sensors available?

If you have the light switch pulled out, will the lights cut out like that? Or is it just when you have the Twilight Sentinel feature enabled only, with the light switch pushed in? I'd hope it's just the 2nd case.

IBx1, 2nd case.
Rick

BMD wrote:

Good to know. Great question and info! Are Ambient Light Sensors available?

...last I checked they were, which makes sense as they are used in many GM cars and have been since the '90s. An FSM helps for R&R but it's not difficult - the moderator moved this post, look backwards and you will find the write-up.

In the meantime remember to use the light switch... if you have to replace the lighting control module, should be able to get a good one from a junkyard (try moradpartscompany.com) for low price.

Albertj

MTRiviera wrote:

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

The repair procedure simply states that the Sensor twists out counter-clockwise, kinda like a headlight bulb. It's just a twist-lock socket. Unplug the connector....reverse procedure.

The GM P/N is 914032. Lists as about $60. The P/N may have been updated by now, but any dealer parts guy can help you with that.

I just replaced mine last year, available from the dealer (recommend an on-line dealer for best price, like monsterpartsonline.com). The installation was easier than I thought it would be. The sensor doesn't unplug when you twist it out like I was expecting - once you have brought the sensor up out of it's socket, it unplugs and plugs in like a little 194 light bulb. I was looking for a plug on the wires... not there!

Great info! I will give this a try and hope that it cures my head light issues.
Regards

Abaddon wrote:

MTRiviera wrote:

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

The repair procedure simply states that the Sensor twists out counter-clockwise, kinda like a headlight bulb. It's just a twist-lock socket. Unplug the connector....reverse procedure.

Ahhhh... That would explain why Rivlanta broke his old one at the top of the page.
(Though I gotta' wonder how the hell you're supposed to get a grip on it that close to the windshield.)

Well, actually no, I knew it didn't twist from the prior posts. It just broke when I lifted up on it with the needle nose pliers. It was very brittle so that's why I suggest you lift very carefully.

It is a tight squeeze, but do-able.

I understand that the sensor plugs straight into the socket, like a 194 bulb, but also like a 194 bulb
the socket has a quarter-turn mount to the grillwork.
I just looked it up, and the factory instructions are to pop out the defroster grill, unscrew the socket
& push it through, and then remove/replace the sensor...

Specifically, the assembly instructions read:

# Partially install the sensor.
# Connect the electrical connector.
# Install the sensor to the defroster grille.
# Turn the sensor a quarter turn in order to secure.
# Install the defroster grille.

this might already be asked. I'm ordering a new sentinel...but what are the two black bulb like projections on the dash there...both sides????

Gracias!

I think these are photocells as well, but they connect to the HVAC system, to control how much air is routed to each side of the car. My parts list says they are: GM #16146093 "Sun Load Temp Sensor"

weird...well I guess they work as I'm cold all over the car now!
Thanks!

There seems to be a lot of back and forth regarding whether or not you pry out or need to give the sensor a twist when removing it. What's the real census on that?

I just changed mine. It pops out. No twist at all. It's like a side marker light...just pushes into the socket. No twisting at all...

oops,posted twice

Twice the reassurance haha thanks!!

Lemme just say it was easier to change the rear plugs in this car than to change this sensor. In fact, the half broken one is still stuck in the dash right now. Will have to just remove the upper dash and defrost grill to even get at it I suppose... why always the designs for people with 4 year old's hands and 4 foot long arms?

llamalor2112 wrote:

Lemme just say it was easier to change the rear plugs in this car than to change this sensor. In fact, the half broken one is still stuck in the dash right now. Will have to just remove the upper dash and defrost grill to even get at it I suppose... why always the designs for people with 4 year old's hands and 4 foot long arms?

Let's just say replacement was not expected to be frequent... this is the same car, mind you, on which you have to remove the entire rear sweepspear (taillight housing) in order to replace a bulb. And don't even start in on the headlights...

I know what you mean. At least those pieces are accessible via fasteners, if not awkward ones. The ones I hate are the parking lights, when one goes out I have to buy a new set of well trim clips because the old ones don't like to hold as strong the second time! Haha It's like everything else on nicer buicks, planned obsolescence of parts to ensure return to the dealership under warranty instead of outside practices. That's been what I can gather. I don't imagine I'll need t o change the twilight sentinel for a good while at least though. I just get so frustrated with tight spaces like that

I just replaced mine in my '97 Riv.  Did all that stuff including removing the metal grill and A pillar trim - unnecessary.  The cell itself can be carefully pried straight up with a dental tool or other small strong lever tool.  The bottom is a bayonet shape with two wires wrapping down the bayonet that engage the female socket in the metal grill.  It can go in either way right to left or 180 degrees rotated.  The cell itself sits under the plastic bayonet hat so that is what can crack if it is brittle from sun exposure.  You can also test it with an ohm meter once out to ensure it is the culprit - not the Lamp Control Module or the headlight switch.

Noticed my lights clicking on and off recently. Read through this thread (Great info as always). First I tried covering photocell, and lights stayed on constant. Then I removed cover, and lights started clicking on and off again. Was thinking maybe the photocell was dirty??? Used a few cotton swabs dipped in alcohol, and lightly rubbed the photocell. First couple swabs got kinda yellow-brown. Repeated several times until swabs stayed clean, and let dry. Then put the cover on and off to check again. Seems to have fixed the problem, time will tell though    ...................

My Twilight sentinel stopped working outside long ago. I recently got a garage for the Riviera, and I noticed that in the dark of the garage, the lights come on immediately upon starting the engine. It is still dark outside as I pull the car out, but 15-20 seconds later, the lights go out, and I have to put them on manually. No big deal, but I was wondering if the newer LED lighting outside triggers the sensor enough so that it thinks it is daylight?

Congrats on the garage. My United U8 led headlights are blazing I am told. After installing them the DRLs will not work and the headlights are on most of the time even during the day which I am good with. The more light the better for the morons on the roads here. I tried to get a photocell out of a junked car. Wires are super short. You might be able to get one out but to me the windshield would need to come out. I got it out but I think I cracked a little piece off the bezel. If you need or want it I will bring it to you. If nothing less you will see better with a good set of led bulbs.

No, I mean the LED street lights and the LED floodlights in my parking lot.  They turn off my headlights in the dark.  When I start the car in the garage, the lights come on immediately.  Pull the car out into the parking lot, and 15 seconds later, the lights go out like the sensor thinks it is daylight.