2017 2500HD LTZ doesn't have LED tail lights??

[timberwolffxdl]

My understanding was that all LTZ of my year (2017) had LED tail lights from the factory.

My truck had aftermarket LEDs installed by a previous owner. The left was giving me an error for having a turn signal out.

I bought new ones, that are for trucks with factory LEDs. But... the tai light harness is wrong.

It looks like the truck end of the harness is setup for standard 3357 (or similar) type bulbs.

First pic is the aftermarket LED, second is the truck harness, third is the new tail light assembly harness.

and yes... I confirmed this is an LTZ both with the original window sticker and the RPO sticker.

Any reason why the truck would have a standard socket-style harness?

[JimCost2014]

Harness probaly came with the aftermarket lights. Did the factory lights not come with the wiring loom? When I recenly replaced my passenger side tail light, the OEM unit came with a new loom attached.

[timberwolffxdl]

5 minutes ago, JimCost2014 said:

Harness probaly came with the aftermarket lights. Did the factory lights not come with the wiring loom? When I recenly replaced my passenger side tail light, the OEM unit came with a new loom attached.

but the harness on the truck side appears to be GM made.  Is it possible someone bought a non LED harness and plugged it in under the truck in order to use the aftermarket lights? Would that even work that way?  If, then I would think I should be able to find a factory LED harness and just swap it back to original

[JimCost2014]

Honestly, as much as the OEM's cost, I would just get 2 new OEM looms to be safe. Aftermarket lights can use the non LED harnesses because resistors are spliced in to stop hyperflash.

[newdude]

1 hour ago, timberwolffxdl said:

My understanding was that all LTZ of my year (2017) had LED tail lights from the factory.

My truck had aftermarket LEDs installed by a previous owner. The left was giving me an error for having a turn signal out.

I bought new ones, that are for trucks with factory LEDs. But... the tai light harness is wrong.

It looks like the truck end of the harness is setup for standard 3357 (or similar) type bulbs.

First pic is the aftermarket LED, second is the truck harness, third is the new tail light assembly harness.

and yes... I confirmed this is an LTZ both with the original window sticker and the RPO sticker.

Any reason why the truck would have a standard socket-style harness?

 

 

 

 

1 hour ago, timberwolffxdl said:

but the harness on the truck side appears to be GM made.  Is it possible someone bought a non LED harness and plugged it in under the truck in order to use the aftermarket lights? Would that even work that way?  If, then I would think I should be able to find a factory LED harness and just swap it back to original

 

 

 

Chevy and GMC HD trucks 2016-2019 did not have the LED tails as an option at all.  That was 1500 only.  

 

The truck side you are finding on your truck is correct and is for the non LED tail lights. 

 

 

If you want to use legit OEM LED tails, you need this - 16-19 LED Taillight Harness – Gen5DIY

Edited February 3, 2025 by newdude

[timberwolffxdl]

Interesting.  Everything I read said the LTZ and HC were the only ones with LED in the HD models in those years.  And the lights I bought (aftermarket) specifically state 2016-19 fitment for 2500/3500 HD, only for trucks with OEM LED lights.

 

Thanks for the link! I'll look into it more

[newdude]

1 hour ago, timberwolffxdl said:

Interesting.  Everything I read said the LTZ and HC were the only ones with LED in the HD models in those years.

 

The trim info is correct there but the HD part isn't.  1500s in Chevy had LED tails on LTZ and High Country, in GMC on SLT, All Terrain and Denali.  HDs were incandescent on all trims, both brands.