Swap 2014 SLE Headlights for SLT w/ LEDs?

MGD · May 14, 2015

Hey guys. I'm the one who did the harness test today on my '14 Sierra SLE crew. The harness works great so far. Here's the overview. NOTE: I had my BCM flashed last month as per service bulletin PIT5374A to increase headlight voltage from 12v to 14v.

* Engine running in daylight, bottom LED's full power no headlights for DRL anymore.

* With headlights on, top and bottom LED's low power.

* All features work fine with switch in auto or manual.

* Another cool feature is that when you lock or unlock the doors the top and bottom LED's come on low power with the park lights just as they do now.

I didn't have the flickering issue like some of you but had a few other issues and now seems to be fine. This harness will have one extra relay and a 12v and a micro mini fuse tap that you will need to install. The fuse tap will go to fuse #50 15 amp O2 sensor. I drilled a small hole on the side of the fuse box cover and covered the red wire on the outside of the fuse box cover with small wire loom (pics attached). Thanks Ofer and Jared for figuring it out. These guys have countless technical hours in this.

Thanks for the photo mafd2, that's a big help. One question though, is there a difference on led operation between those of us who had the flash and those who haven't besides headlight power(not sure how it could but with computers you never know anymore)?Also, Big thanks to Ofer and Jared for quickly tackling this problem!

2SSRS · May 14, 2015

Thanks for the photo mafd2, that's a big help. One question though, is there a difference on led operation between those of us who had the flash and those who haven't besides headlight power(not sure how it could but with computers you never know anymore)?Also, Big thanks to Ofer and Jared for quickly tackling this problem!

We were able to repeat the flashing LED's on our truck, we tried capacitors, load rissister, and many more things to fix the flashing LED's, when we got the LED's to stop flashing the headlight did not come on in auto mod, what we did with the new harness is separated the computer from the LED's and that fixed it.

MGD · May 14, 2015

We were able to repeat the flashing LED's on our truck, we tried capacitors, load rissister, and many more things to fix the flashing LED's, when we got the LED's to stop flashing the headlight did not come on in auto mod, what we did with the new harness is separated the computer from the LED's and that fixed it.

Thanks Ofer, I guess I should proofread my posts, You probably covered it but what I meant by flash and I should have specified was the update from 12v to 14v operation on headlight with the new harness. Thanks again. Mike

2SSRS · May 14, 2015

When i talked to mafd2 his truck was updated from his dealer for the 12v to 14v so it works, what we are doind will not change that fix.

MGD · May 14, 2015

When i talked to mafd2 his truck was updated from his dealer for the 12v to 14v so it works, what we are doind will not change that fix.

That's what i thought. Thanks again Ofer

mafd2 · May 14, 2015

That's what i thought. Thanks again Ofer

I checked the voltage where the micro fuse tap goes and with the engine running, it's getting 14v as you would get with the BCM update and 12v not running.

As per Jared with Gen5 here's what he told me. "With our harness you are actually getting a pure power source, versus going thru the BCM. In theory we kind of performed the service bulletin to your truck without re-programming the computer. The voltage was always there in your trucks, the BCM was just regulating how much was being sent to the lights".

MGD · May 19, 2015

Ok, installed the new harness , headlights didn't work, truck idled rough, emailed poor Ofer and then looked a little closer at mafd2's fuse picture and noticed I forgot to add the existing fuse to the jumper. Was kind of hard to make out with my eyes but hooked it all up and working fine! All is well , sorry again Ofer. .....dang seeing eye dog

CruseMissle · May 19, 2015

Can't wait to get mine hopefully I get them soon

mafd2 · May 19, 2015

Ok, installed the new harness , headlights didn't work, truck idled rough, emailed poor Ofer and then looked a little closer at mafd2's fuse picture and noticed I forgot to add the existing fuse to the jumper. Was kind of hard to make out with my eyes but hooked it all up and working fine! All is well , sorry again Ofer. .....dang seeing eye dog

Lol don't feel the lone ranger. After I finished the testing for Ofer and Jared,, I removed the fuse tap and forgot to put the 15A O2 sensor fuse back in it's slot. Started it and what the f*#I<! Running like crap! Realized what I did and put the fuse back and "voila", running good. The check engine light stayed on for a few mins then cleared. Glad you got it working bud. Chris

MGD · May 19, 2015

Lol don't feel the lone ranger. After I finished the testing for Ofer and Jared,, I removed the fuse tap and forgot to put the 15A O2 sensor fuse back in it's slot. Started it and what the f*#I<! Running like crap! Realized what I did and put the fuse back and "voila", running good. The check engine light stayed on for a few mins then cleared. Glad you got it working bud. Chris

Thanks! Yeah it was one of those Oh crap moments but all is well! Now on to the next project! Mike

whodatfan · May 19, 2015

Got the new harness in yesterday and all is good. Lights work perfect. I have a new problem not related to harness. I have 2 different lights. One that was brand new that I got from that carparts .com site before they were sold out and one that was used from another truck that had a tab repaired. Well, the LEDs do not match. New light is a bright white glow and the used one has a more soft white glow. Pretty noticeable difference. Sucks, but they work properly.

mafd2 · May 19, 2015

Got the new harness in yesterday and all is good. Lights work perfect. I have a new problem not related to harness. I have 2 different lights. One that was brand new that I got from that carparts .com site before they were sold out and one that was used from another truck that had a tab repaired. Well, the LEDs do not match. New light is a bright white glow and the used one has a more soft white glow. Pretty noticeable difference. Sucks, but they work properly.

The one from carparts was probably an older light and the first that came out which had "yellowish" looking LED's. The newer ones are a brighter white. Check the build date on both lights and compare. Mine have a Jan 2015 build date.