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Hello everyone.


I purchased a complete set of LED bulbs to replace all the stock bulbs for my 2012 GMC Sierra 2500 HD. In addition, I upgraded the tail lights and the head light assemblies as well to house these new bulbs. I'm very happy with the complete change-over except for the hyper flash issue I'm having with the new LED turn signals.


Originally, I thought I could just replace the original flasher for an LED flasher that doesn't monitor the load on the circuit and therefore operates normally with the light-loaded LED upgrade. Turns out that the 2012 doesn't have a flasher and it's the BCM that controls the turn signal lights. From what I've researched, it appears that the BCM can be programmed to allow the use of LED's by changing the configuration of the BCM to a "cab/chassis" setup where the vehicle would accept the LED tail lights. I'm guessing that with changing everything including front turn signal bulbs to LED, the BCM reprogram to "cab/chassis" will not fix my issue because I've changed the front turn signals to LED as well.


The other option I've researched is installing load resistors for every LED bulb. That seems a bit outrageous and hacking into the original wiring harness is not what I'd prefer as it makes it more susceptible to malfunction, corrosion, etc. not to mention the heat these resistors tend to give off, if installed improperly, can begin causing a whole other bundle of issues.


So my question is, will the BCM reprogram resolve the hyper flash issue? Depending where you are but most dealers will charge $120 - $200 for the 3 minutes it takes to plug in but if it fixes the issue, I'd rather go that route instead of hacking my wiring harness.


Thanks in advance for any help!

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I called my dealer today and they told me they don't do it for consumers. I'm in South West AZ. Per the Service specialist they only do it for government vehicles and then they have to fill out a form to get the BCM flashed.

Here are some other posts I've found regarding the BCM flash.

https://gm.oemdtc.com/4610/bcm-calibrations-to-restore-bulb-outage-detection-turn-signals-flash-fast-2007-2016-chevrolet-silverado-gmc-sierra <- GM Tech II info on BCM programming options


http://www.duramaxdiesels.com/forum/showthread.php?t=55843 <-Best thread with most responses

http://www.silveradosierra.com/electrical/dealer-reprogram-bcm-for-leds-t245442.html <-Some references to BCM flashing

http://www.gmfullsize.com/threads/led-hyper-flash-2500hd-custom-bed.278672/ <- This dude built his own flatbed with LED's, and was given info on flashing the BCM.

I found a technical bulletin for these year trucks, hopefully it helps



And the website where I found it


Edited by JetForceF22
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  • 1 year later...

There is a reflash program that costs fifty bucks and 1 hr labor to fix and correct the issue . Using the resistors is putting lipstick on a pig and it will if not cause damage to your electrical system.  How Do I know , I have a western hauler bed on my 2011 Denali and with LED lights galore and I have to have it done in Florida , because that hyper flashing is driving me insane . 

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  • 7 months later...

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