Silver-ado

Question for the electrical gurus... I’ve installed a flatbed on my 2016 GMC Sierra 1500 SLT. All of the lights on the bed are LED as well. I have no issue wiring the lights to function properly, however, I don’t know what to do with the red BCM signal ground wire. It makes no difference if I tie it into the ground circuit at the light or not I still get hyper flash. I chose to wire into the existing tail light sub harnesses to avoid the hyper flash I expect if I were to wire directly into the trailer plug. How closely would I have to match the load into the BCM to prevent hyper flash? I didn’t expect to have to add resistors as you would in a typical incandescent to LED conversion. LED to LED I didn’t expect to have an issue. Any help would be much appreciated!

Have any of you guys had an issue with moisture in these LEDs? I’ve seen that desiccant packs work well in the non-LEDs, can the turn signal socket be removed and a desiccant pack put in? Otherwise these are sealed units...

I also had (and still have) an occasional clunk on deceleration, hard downshifts, and indecisive shifting. After mentioning it several times to my dealer they decided to look into it. After several weeks (and 600 miles they put on it) they had replaced the TCM with no change, and then the whole 1-2-3-4 clutch housing. I would say it improved the issue(s) 70-80% at first. After a 1,000 miles it's back to the hard downshifting and clunking. I'm starting to think it's just GM's POS trans tuning as well. I don't really know where to go, sell it back and loose my ass on it, just drive it and deal with it, or go for an aftermarket tune and hope I have no catastrophic failures in the future. I've starting running it in m5 all the time except on the highways. That seems to help the shifting a good bit, taking AFM out of the equation, however the hard downshifts/clunks are still there.

Nofastcar, was the dealer able to find anything?

Nofastcar, did you ever find a fix for this? I'm right around 5,000 miles now and have developed this same issue. I was thinking it was more of a transmission issue but I'm too having the "clunk" when downshifting and coming to a stop. Dealer says it's normal, it's getting really annoying... Thanks,

I finally took my truck in for this. I had to describe the TSB to the tech and he was able to look it up after 10-15 minutes. The bulletin number is PI5137C per my service report. It seemed to help the vibration issue at idle, it's still there though.

I've recently been experiencing a rough idle like hotrodz37. The dealer performed a motor mount alignment procedure on both the driver's and passenger's side mounts when I took it in (no shims were added though). The vibrations never really went away, and now they are back full force at idle. Could someone show me where to find the actual TSB for the 3mm engine shim so that I can take it with me to the dealer? Thanks,