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I wound up buying a 2017 LP5 this past February. I decided to buy a new truck at the end of February and decided to go with Butte Red. I had to purchase the truck before the 28th in order to get all the rebates as well the additional GM Card $$$. Criswell Chevy found me the exact truck I wanted but it didn’t have the roof marker lights. I have always had cab lights on all my trucks so I decided I would install them myself. Please use your own judgement if you decide to do this!!!

There are a few threads on this site for installing the lights but nothing specific to the 2017 truck. So I figured I would post a brief write up on how I did it...

To start, I did some searching to determine what parts I needed. I wound up ordering the following parts (through a Chevy Dealer on eBay)...

22794642 Left Light
23463750 Center Light
22794643 Right Light

For the wire harness, I found a part number for a 2015 truck. I found dozens of parts numbers for the harness, all for trucks with various options, such as sunroof, rear sliding window, certain radios, etc. I settled on this particular harness and I’ll explain more late...

23170769 Wire Harness

To help determine the exact locations on the roof, I called a friend of mine who bought a 2016 Denali last year. I asked him to stop by so I could take a handful of dimensions...



And this is the sketch I put together...



More to follow...
 

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Once I received all the parts I laid everything out to start. I also bought an “Auto Trim Removal Kit” off of Amazon to help drop the headliner. These are the blue tools and they work great. They are reasonably priced and sure beat using a screw driver to remove plastic plugs, etc...



The first thing I had to do was drop the headliner. Not all the way, just a few inches that would allow me to run the wiring, etc. I started by removing the overhead console. I found this link to help with dropping the console...

https://www.gmupfitter.com/files/media/photo/588/UI Bulletin_123.pdf

I then removed the visors, A pillars, etc. I like to put the screws and bolts back in the same spot I took them out of so I always use a piece of cardboard to keep everything in order...



Once I had removed all the hardware I was able to pull it down a few inches...



The interesting thing about these cab lights is that they are fastened to the truck using a 3/4" square hole. To help lay them out of the roof, I used some thin cardboard. I started with cutting a 3/4" square hole out with an exacto knife and then inserting the cab light into the cardboard...



Then I traced the perimeter of the light on the cardboard...



And then I cut the pattern out for the light. I did this for all (3) lights, although you could use the same one for the left and right (just flip it upside down...)



More to follow...
 
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Once the patterns were done, I used some green painters tape to cover the roof where the light would be located and then set my cardboard pattern in place. To help with the measurements, I used a 7” soft plastic ruler that came in a goody bag from a car show. I have a bunch of these and the work great taking measurements on curved surfaces...



I then moved on to the center and left lights. After I had found the exact location I wanted, I used some additional tape to hold the pattern in place. To help find the centerline of the roof, I used my rearview mirror for reference. I marked the centerline on the roof and then double checked it on both the left and right sides. It’s sort of a difficult job by yourself since the roof is curved and you’re trying not to scratch anything...



After I was happy with the locations and traced the square holes on the green tape, I used my Dremel with the small cutoff wheels to cut the holes. I used my Dremel almost every day and it works really well. I stuffed a towel below the headliner to minimize the sparks and dust also. For the top side. I used some 3” wide tape and folded it in half (then formed an “L”) to help control the sparks and dust....



After the holes were cut, I used a small flat file to clean the edges. The holes were slightly smaller than what I needed to fit so I carefully filed each one to fit the light. I would rather have the hole too small at first then too big. Once each hole was filed, I painted the bare edges with some leftover touchup paint I had.



More to follow...
 

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While waiting for the paint to dry, I turned my attention to the wire harness. Since the harness I bought didn’t match the exact options my truck had, I made the decision to gut the new harness and only use the wires that I needed. In this case it’s the purple and black wires. It took some time to remove all of the tape and clips, but at the end I would up with just the two wires I needed.

The marker lights are fed from a fuse box that is located on the passenger side of the dash. The side cover is removable and I used some of the interior tools I bought to help pull it off. It’s very difficult to remove the first time since the clips are stiff. So just take your time and work with it. Once you have the panel off, you will see a long gray plastic plug on the bottom of the fuse box. I forgot to take a pic of my fuse box but I found this one online and added my notes...



Taking the harness I just gutted, I removed the clip on the plug and was able to pull the purple wire out with a small screwdriver to release the plastic clip. Just go easy here so to don’t break the plastic. This is the plug I removed the purple wire from (from the new harness I bought...) For the thin black ground wire, instead of splicing it, I cut off of the donor plug and used a 1/4" eyelet on it. I then put it behind one of the studs I noted in the pic above.



Once I was happy with the wiring, the touch up paint was dry so I went ahead and installed the cab lights. I used a bead of silicone around the foam gasket that is underneath each light. They don’t use any type of sealer from the factory but I didn’t want to take any chances. I have read a handful of threads where people have had water leaks from either the marker lights, SiriusXM antenna or third brake light.

Be careful not to overtighten the mounts on these lights!!! Once the lights are bolted down, there will still be a small gap under the perimeter of each light. I noticed this on my friends 16 Denali since my plastic ruler slid underneath them when I was trying to measure them.

More to follow...
 

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After carefully routing the wires and using some 4” wire ties, I connected the plugs to each of the lights and ran the wires in the pillar. Then I did a quick test just to make sure everything worked...



After I was happy everything was working, I buttoned the headliner back up and took the truck outside...



These make all the difference in the world!!!

Hope this helps!

Tom
 

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Roof Marker lights

I did the same thing this week on my 2016 2500 High Country. First rain got moisture in the lights. I could see in in the lens. Used a hair dryer to dry them out and sealed the light all the way around.
 

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Discussion Starter #8
They make several different wire harnesses for these trucks, depending on the year, options, etc. My truck came with the plow prep package which means it doesn't have the rear sliding window or Homelink. Some trucks have a combination of sunroof, rear sliding window, etc... So there are several different harnesses they make. In my case I figured it was easier to remove the two wires I needed rather than replace the entire harness.

On other threads, it has been recommended that you find a truck with the same options as your but with the roof marker lights, write the VIN down, and use that to order the correct wire harness from the dealer.

Hope this helps...

Tom
 

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Thanks for explaining. I was under the impression the harness was just for the cab lights and plugged into an empty spot in the fuse block. This is how it worked on my 2006. But your saying that there is already an existing harness that goes up there that needs to be replaced?
 

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So the cab light wires/harness is tied into a bigger harness? The reason I think I am confused is when I added cab lights on my 2006, i just had to buy the gm harness than plugged into the fuse box on the passenger side and it ran up the pillar and powered the lights. This isn't the same? The cab light harness does other functions too?

I have a Denali hd with sunroof and power rear window. That's why it don't have cab lights. I want to add them myself and thought there would be a single harness to run to power the cab lights like the 2006 was.

Sorry if I'm being confusing
 

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So the cab light wires/harness is tied into a bigger harness? The reason I think I am confused is when I added cab lights on my 2006, i just had to buy the gm harness than plugged into the fuse box on the passenger side and it ran up the pillar and powered the lights. This isn't the same? The cab light harness does other functions too?

I have a Denali hd with sunroof and power rear window. That's why it don't have cab lights. I want to add them myself and thought there would be a single harness to run to power the cab lights like the 2006 was.

Sorry if I'm being confusing
It certainly can have power sunroof, power rear window, and cab lights. Mine has all three.
 

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I think the confusion might be with the provision for the emergency roof lamp with the snowplow package.

There is no restriction for the clearance lamps -- and they are standard with the drw trucks.


These are from the 2017 Denali order guide:

VYU Snow Plow Prep Package, includes power feed for backup and roof emergency light, (KW5) 220-amp alternator with gas or diesel engine, forward lamp wiring harness, (TRW) provision for cab roof mounted lamp/beacon, (NZZ) underbody shields and Heavy-Duty front-springs
- Only available on 4WD models. Not available with (CF5) power sunroof. When (VYU) is ordered (UG1) Universal Home Remote and (A48) power sliding rear window is deleted. Upgradeable to (KHB) dual, 150 amps and 220 amps each alternators with (L5P) Duramax 6.6L Turbo-Diesel V8 engine.


U01 Lamps, Smoked Amber roof marker (required with dual rear wheels)
2500 - Not available with (YF5) California state emissions requirements.
3500 - Standard with dual rear wheels. Not available with (YF5) California state emissions requirements on single rear wheels.
 

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To the OP.. the harness you bought just had more than you needed so you eleiminated the extra wires/plugs? Or did you incorporate the new harness with the harness that was already installed in the truck from the factory?
 

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Hi Dan33klein...

There is not a separate harness for the marker lights, like the 2006 had. There is only one wire harness and everything is incorporated in it. So instead of trying to replace my existing harness with a new one, I felt it was easier to remove the two wires from the harness I bought and add them to my existing harness. Basically I used small 4" wire ties and ran the wires parallel with my harness.

I didn't mean to add confusion about the snow plow prep package, etc. I guess I was trying to explain that there were numerous options for the roof harness.

Does that help? If you need more info just let me know...

Tom
 

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Tom, were good now. Looks like I will have to do the same. Not to thrilled about spending 100$ just two use 2 wires and the plugs though. But I guess it's the right way to do it.
Thanks
 

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Hi Dan...

I agree, I wasn't happy about spending the $100 either, but it would probably be a lot harder to find the correct plugs and terminals not only for the marker lights but for the plug in the fuse box also.

Tom
 

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Hi Dan...

I agree, I wasn't happy about spending the $100 either, but it would probably be a lot harder to find the correct plugs and terminals not only for the marker lights but for the plug in the fuse box also.

Tom
Yeah, thats crazy for $100. The whole roof marker light option was like $55 when I ordered mine.
 

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Dealer just got back to me and said inneed part #23263979

This is the harness for cab lights/power rear window/ and moon roof.

Lions- I assume this is the harness yours came with from the factory.
 

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Dealer just got back to me and said inneed part #23263979

This is the harness for cab lights/power rear window/ and moon roof.

Lions- I assume this is the harness yours came with from the factory.
I am assuming that you are probably right. I can't tell from the picture, but here is mine at the factory! The picture is a little blurry, I blew it up, to just show the top of the cab.
 

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