MightyBobo

Hey man, I didn't take a picture of it while I was doing it because I was so infuriated with the poor instructions. You should have the same setup as mine. I made a quick diagram for you. when you are in the foorwell looking up, you will see these 2 boxes toward the driver's side wheel, to the left of the brake pedal. The closest, lowest BCM has 5 plugs in it. Normally, that open one in my photo has the pink plug in it. Ignore them. What you want, is the uppermost box that has 8 plugs in it. Note, the instructions are WRONG - not only does it say 8 plugs in one place and 7 plugs in another, but the orientation arrow is incorrect too of course. I better highlighted the port you will need in red, but the plug design looks exactly like the one below: you want the 1st position. Be very, very careful removing the thin, white insulator from the side. They break easily. Furthermore, the wire only goes in one Finally, the wire DOES have an "orientation" that it must be in to go in properly. It has a tiny little spring-loaded top on it, that is narrower than the rest of it. The port is shaped like below, with the top of the shape being in line with the top of the plug oriented above. If it doesn't go in easily, something is preventing it from doing so - in my case, I needed to squish down the portion where the flexible wire met the more rigid metal end, because that simply was too "thick" to get in all the way. Once I did, it slid right in without ease, and the spring-loaded top will lock it into place. It should NOT come out. If it isn't doing the same for you, something isn't quite right. Do NOT FORCE IT - it can be fragile. Hope this helps, tell me how it goes! I think I'll make a write-up or perhaps a youtube video about this because I 100% know I was not alone in struggling with this.

Final update: I figured it out. Pretty damn furious, because it's GM's instructions that were bad. The arrow for orientation of the truck in the diagram is literally backwards. It was, indeed, the very back, upper box...and to make it worse, it was the connector on the OPPOSITE end of the box, closest to the firewall. It's difficult to get to, putting it mildly, but once you get it out, the single power plug does indeed go right into the port shown in my picture above. So, for anyone else searching for this endlessly, I'll save you a lot of time, I hope: IT'S THE BLACK ONE TOWARD THE FRONT.

Also, getting under there, the closest box is part # 13547244 - this returns a BCM for a 1500 Sierra and Silverado...and it only has 5 ports. https://www.ebay.com/itm/276439287948

So, looking at my first photo, it's the connectors buried farther back in the photo with 7 connectors then? Then I run into the issue where the connector does not look at all like the one in the instruction manual, here. I'm mainly talking about the 4 larger openings on the bottom. Also, it looks like the very top left port on THAT one is occupied, as well.

*UPDATE 17 May*: IF YOU ARE TRYING TO FIGURE OUT HOW TO INSTALL THESE, GO TO MY COMMENT BELOW WHERE I FIGURED IT OUT Hello there! So I am working on installing these door sills using these instructions (because of course, on GM's own site, the instruction file failed to open) into my truck, and I am stuck on step 23, which is where you're connecting the power source to the BCM connector. Namely, the connector itself appears to have cavity #1 already occupied. The reference photos also don't really line up either - in the photo below step 25, I see two boxes with connectors but the closest box only has 5 - the one BEHIND it has 8...so am I pulling the wrong connector entirely? Have this all torn apart right now, and could really use a hand quickly!

I just wanted to throw a new link to the original PDF file here. The new one posted above looks like it was copied 30 times over with a 20 year old photocopier lol. Instructions look the same regardless if it's a Denali or Silverado. Document ID's match. Whomever made the PDF did squish a lot on each page, and step 22 (maybe others) are cut off, so be wary. https://www.duramaxforum.com/attachments/denali-illumimated-door-sills-pdf.1116830/