2015 Tahoe Disco lights

[tenyearguy]

Has your Tahoe's lights done it again since the repair?

Not once!!!!!

 

[BobbyD]

I have had both Dome light modules replaced twice. still flicking and happens while driving, worst when its colder outside

 

[brittanytahoe]

I have the same problem. I have seen in other forums that the resolution now is to replace All lights and the computer that control radio, alarm, door locks, etc.

 

[Tylus]

the dealership has to replace every single LED inside the cabin. they're all a faulty design. replacing just the dome lights does nothing

 

[bigmoose]

Finally driving mine enough at night to pick up a pattern in the flashes. Taking it to the dealer tomorrow. I am getting close to the 36,000 mile limit; so specific direction on an effective repair is appreciated.

Does anyone have the updated PI1268 TSB? Does it say what part numbers are replacements? Is the computer that controls the lights, locks etc on the revised TSB?

 

[bigmoose]

Very thankful for the wisdom on this web site! Got mine repaired at the dealer this morning, and I think I understand what is happening a little better. Note that some of this is conjecture. (I'm a EE that did spacecraft power systems for 35 years)

My complaint to dealer: Second row "dome" lights random flicker/flash on first startup. Seems to correlate with brake light application. Did not seem to happen during evening/nightiime driving. I told them about PI 1268 right from the beginning.

Dealer acknowledged PI1268 and took action based on it. They replaced Qty(2) light modules in the front center console, part number 23104411.

I got to talk with the tech and see the old modules, but he wouldn't let me take the circuit board out as they had to return warranty parts. My observation was that the 1 inch square circuit board was "smart" as in it likely had a microprocessor on it.

My conjecture: The second and third row lights are slaved off the front modules. The front modules have a microprocessor in them. That microprocessor has a "brownout" feature, that reboots the micro after a power outage, or a glitch. With age ( my Tahoe was bought in 12/2015 and has 32,000 miles on it) a critical component has drifted in value and/or the power line glitches have gotten worse. Under certain conditions the microprocessor is doing an automatic reset and rebooting. The flash is coming from the instant the micro reboots, before it runs through its startup code for the first time to extenguish the light.

I have seen this type of behavior in my regular work, and oftentimes we can solve it with additional filtering on the main power feed. I would propose that if anyone has this problem, and is skilled in small scale electronics that you add a couple of uF to the rails on the input to the microprocessor. To the others, that means add some capacitance to the incoming power supply to the module, as close to the microprocessor as possible. This helps to "stiffen" the rails and lessen transients and hash on the line.

If anyone has the detailed schematic of this lighting sub system, and/or wants to send me a defective module, I will try to add the capacitance, and then show a picture of where to do it. I can't guarantee I won't fry the module.

If you have this problem, make sure your dealer knows about PI1268. The reason for this lengthy reply was that the service guy and the technician came to me and asked my opinion, as an engineer, on why changing the front module would solve a problem further down the chain.

If this fix does not work (changing the 23104411 module) I will post again.

 

[DWTahoe]

Thanks for all the information in this post. I'm dealing with the issue at 40K miles so no warranty. I tried to open a case with GM and they pretty much said no recall--no chance of us helping out.

Updates I got that may be useful is the PI number has moved to PI1268b and they have updated part numbers for the modules, I will add those when i get back to the house if they are different than the ones in the reply from bigmoose.

I believe I can find the parts for around $35 a piece and now I'm just checking if anybody has instructions for pulling apart the front dome light overhead assembly? I think that is what needs to be replaced. If anybody has any pictures that would be great. ~Dan

 

[STORMCAT]

New here ,, and having the same problem in my 2015 Tahoe 35 000 mile. Lights flicker in all three rows when brake pedal is depressed .. Thank you all for sharing this info !!

 

[DWTahoe]

New here ,, and having the same problem in my 2015 Tahoe 35 000 mile. Lights flicker in all three rows when brake pedal is depressed .. Thank you all for sharing this info !!

Get it to the dealer before you run out of warranty....... ;-)

 

[04ctd]

add some capacitance to the incoming power supply to the module, as close to the microprocessor as possible. This helps to "stiffen" the rails and lessen transients and hash on the line..

PI number has moved to PI1268b and they have updated part numbers for the modules,

well, a change in PN would indicate that they added the capacitance BigMoose suggested, and it should be fixed now.

are the 2016's having this problem, this post with the updated PN is Nov 16, which means the old PN would have been used in early 2016 builds....ouch!

 

[DWTahoe]

Sorry I forgot to update what I had. As of last week GM wanted no part in helping or resolving this. However, my dealer is looking to help as much as they can, so we'll see what they come back with.

As I mentioned before the PI # changed and the part number they gave me for the modules is now #23396157. I believe there are 2 of them for the front overhead lights and although those front lights don't flash they are connected to the 2nd and 3rd rows, which do. If anybody has pulled apart that front overhead console I'd still love to see what that procedure is. I may still end up having to fix it myself. Thanks.

 

[04ctd]

You just cancelled my plans for a 2016....last thing I need is, $70k disco light system

 

[DWTahoe]

You just cancelled my plans for a 2016....last thing I need is, $70k disco light system

Others will have to chime in, but I think it's only an issue with 2015's. I think the later models have the updated modules. No Disco party for them....hopefully.

 

[Tylus]

http://gm.oemdtc.com/2492/pi1268b-d...-turn-signal-2014-2015-cadillac-chevrolet-gmc

This TSB #PI1268A was referenced on my work order when I finally got the damn Dealership to fix the issue. Google showed the link above.

hope this helps

 

[Duff87]

I have the same issue but I am over my 36k warranty will gm still fix the issue for free or am i f@@ked?

 

[DWTahoe]

Probably depends on your dealer, I would try and get them to do it. Every dealer i talked to said they had never seen the issue before but if you reference the PI numbers in the above posts they may be able to help you out on the diagnosis cost.

I'd guess you will be paying for it. But, hopefully they will help you out. Good Luck, I hope you have better luck than i did.

 

[Duff87]

had anybody found the parts, since reading the updated bulletin it should only be two lamps right?

 

[Mike Daugherty]

It will take appx 15 minutes to remove the bezel, replace the lights and re-install. 23104411 is the part number, I bought two on EBAY for $23 each. Worked like a charm.

The overhead panel is actually 2 pcs. Snap out the small panel that holds the HomeLink, rear hatch and dome light controls- just pull down on the rear portion of this panel to pop the clips out. This will allow you access to the two screws that hold the larger panel to the roof, you will need a fairly long Phillips screwdriver. After the screws are out, pull downward on the front of the larger panel, there is one clip in each front corner that will pop out, I had to use a flat screwdriver in each corner on this. You then disconnect the main wire harness and both units will drop from the roof. Swap the lights out, a simply re-install the overhead unit.

 

[Duff87]

Thanks

 

[DWTahoe]

Mike, just for clarification when you say pop the "rear" of the panel, do you mean the section toward the rear of the vehicle? I just want to make sure before I go pulling on the pieces.

And just for reference I think this is the new/updated part number I found with my dealer (#23396157) as the old one shows discontinued on a few sites.

Thanks for posting how to get that panel apart I've been looking for it for a while.