the exhaust pipe from the cats to the muffler is 3.5 in compared to the 5.3 3in. I love the fact that know one knows i have a 6.2. I so happy when i realized there was no tag anywhere saying 6.2.

 

Headlights on 14-15 sierras totally suck you may know already but if you didnt now you do. You will be sorely upset going from headlights in your old truck to 14-15 model past that solid as a rock they are

 

I have a 14 and the headlights are excellent, not sure what you mean by they totally suck

 

Haven't had a problem with mine either. Yet?

 

Ok let me clarify then mine were not near as good on a 14 I had versus the stock light output of my gmt-900. I've heard several people complain on here through the years and a virtual **** ton of people complaining at the shop. So much so gm finally issued a tsb for reflash and brighter bulbs which was a eh semi solution. It was enough of kinda improvement it took care of most people complaining about them. The LED's on 16 up zero complaints. Light outputs a personal perception deal I want to see and give others a sunburn personally.

 

My lights are so bright I literally worry I'm blinding people.

It's not just perception thing, it's a consideration thing.


I had to go look up that recall and apparently my truck is one that would be one of the affected trucks, I'll have to look for signs of the recall being done, I'd be surprised if they are supposed to be brighter.

Found this below:







Headlamp Performance
April 10, 2015On some 2014 Sierra 1500 and 2015 Sierra models, poor headlamp performance may be noticed when driving in very dark rural areas. While the headlamps meet all Federal (FMVSS) requirements, some owners may request better headlamp performance.

When addressing headlamp performance conditions, normal diagnostics should be performed first. Verify that all headlamps operate properly, headlamp adjustment is correct, and there is not any headlamp mounting damage or concerns with the lens (e.g., haziness, cloudiness, etc.). Repair any headlamp conditions. If an owner still has a concern, perform the following calibration and bulb repairs.

Build Dates

For vehicles built before December 23, 2014, at Flint Assembly (11th VIN Digit “F”), before January 13, 2015, at Silao Assembly (11th VIN Digit “G”) or before January 16, 2015, at Ft. Wayne Assembly (11th VIN Digit “Z”), reprogram the BCM with the latest calibration available in TIS2Web starting on January 12, 2015. The new BCM calibration will increase the voltage to the headlamp bulbs in both the low beam and high beam settings.

All vehicles built after these build dates have the new BCM calibration and the BCM reprogramming does not need to be performed.

Headlamp Bulb

Next, replace both headlamp bulbs with updated bulb part number 23342527. Verify the correct bulb is being installed by confirming the correct markings on the bulb as shown: (Fig. 12)

1. 28432
2. HIR2+30



When installing the new headlamp bulbs, do not touch the glass. Make sure the bulbs are fully seated into the headlight housing. If the bulb is not properly installed, it can lead to an incorrect light pattern.

The beam pattern photo (Fig. 13) shows the low beam pattern of a properly installed bulb on a Sierra (one lamp with the opposite lamp blocked) on a wall/aiming screen at 25 feet (7.62 m). Each block division is approximately 10.5 inches (26.67 cm).



Headlamp Aiming

After bulb replacement, refer to the appropriate Service Information for the Headlamp Aiming procedure.

TIP: The bulb replacement and the calibration change should be performed at the same time. Performing these repairs at the same time will show a dramatic improvement.

 

I've been waiting until the slow season before I take my truck in. Have several recalls to do. Seatbelts etc. Don't guess there is a time limit?

 

Not on safety items. My 21yr old Buick still gets notices in the mail about engine bay fires haha.

 

If it's a 6.2 double cab the tailpipe is actually 3.5" as well. But that is only double cabs and nobody wants those so it's gone mostly un-noticed.

The headlights on the 14 and 15 GMC trucks suck even with the BCM voltage adjusted. The safety department at the large oil company I work for ( biggest in Canada) banned the Sierra's from being purchased because the lights sucked so much with all the night time driving we do in remote area's. They lifted the ban in 2016 with HID equipped trucks and started running Sierra's exclusively again as they always have. We have one 14 Sierra left that has the new Vosla's and the voltage adjusted and it's still useless at night lol. It's a night and day improvement over the original setup but it is still dim enough that the transition from low to high is pretty unimpressive. It will be gone this fall and replaced with a 2019.

 

Look on the glove box door. It has all the option codes.
L83 = 5.3
L86 = 6.2