JR777

same here I added the homelink the first week that I purchased the vehicle. I purchased a brand new console from www.newgmparts.com and pluged it in for less than $200. At the time there weren't any available on ebay Oh well

I'm not positive but there are several locations for various functions at the BCM. Look at the up-fitter manual and find the junction blocks. Look for the circuits that you need here. It is safer to tap into the junction block than it is to tap into BCM. As for BCM flashes and VIN numbers they ARE NOT necessary. A flash would be needed to change software. For example. On your info screen when you program different functions an LT would be missing features such as memory options. If you were to flash the memory with a VIN# from a different vehicle your computer would detect missing components and trigger a warning lamp on your instrument cluster. Not even sure if 2015 and later can even be flashed. I will try to locate the appropriate pages and edit this post as I remember the information. I wasted a lot of time and money on this mod and if I had to do it again I would be able to breeze through it. looking back at the very early post on this subject people are making it more difficult than it should be. When I purchased my vehicle last year even the mechanics at the dealership told me that it was impossible. I guess because of warranty issues. Here is a list of most of the pages you will need. Browse through the whole thing when you can. Very interesting. wiring schematic starts at p.26 to about 54. You may as well start at the beginning and skim through it all. component location starts on p.196 Junction blocks start on p.277 inside rearview mirror p.297 Body Control modules (BCM) start on p.485 Outside rearview switch p. 700-701. This is where you can see the different harness configurations for the mirror switches. Headliner to overhead console. p. 833. To identify wires to hook up ,say radar detector etc Door to body harnesses start on p. 845 Outside rearview mirror to driver door harness p.852 Outside rearview mirror to passenger door harness p.860. P.S. when you get to the correct gm-upfitter site and locate your manual, download and save it to your computer as a PDF file so you can easily breeze through the pages whenever you want.

To get auto dimming to work you will need proper dimming interior rearview mirror. I purchased mine on eBay for $35. I was also lucky enough to buy one that had both sides of the mirror harness. Of course one side was cut but from this I unpinned the three extra wires that I needed. With the three wires that had pins on them from the purchased mirror I inserted the pins into proper harness connector holes. I would imagine if you don’t have the leads with pins you could tap into the mirror directly. I then soldered these wires to a CAT5 cable long enough to run from the interior mirror inside the front edge of the headliner down the pillar and ending at the firewall left of the brake pedal. This is where you will attach the three wires for the dimming feature. You will attach them to the X61A-X3 junction block. With my truck 2015.5 LT (Not sure 2014) there was no need to run any wires on the inside of cab to the door harness. They were already wired.You will need to add appropriate wires to the outside mirror harness as well as door harness. Use the same procedure for dimming wires as you did for turn signals and puddles..The three wires that you will be adding to the new interior mirror are, Pin #1 circuit #24 L-GN/WH (Backup lamp supply voltage).Backup lamp voltage turns dimming off in reverse so you can see where your driving. Pin #8 circuit #1691 BK/YE (Automatic Day/Night low reference). Pin#9 circuit #1690 YE/WH (Automatic Day/Night mirror signal). Wright down the color of the wires that you are running to the junction block. The junction block X61A-X3 is located on the firewall left of the brake pedal. X3 will be a blue colored harness connector. You can tap the circuits from the front but I didn’t want anything visible to the dealership so I unbolted the junction block (3 nuts) and tapped into the circuits from behind. The CAT5 cable is not visible from anywhere inside my truck and since I decided to use a donner door harness for all the extra wires that I needed, you can not notice that I modded my door harness. The three circuits on the junction block are as follows Pin#8 circuit #1690 YE/WH (Automatic Day/Night mirror signal). Pin#9 circuit #1691 BK/YE (Automatic Day/Night mirror signal). Pin#13 circuit #24 L-GN/WH (Backup lamp supply voltage). Backup lamp voltage turns dimming off in reverse so you can see where your driving Note the corresponding circuit numbers and wire color codes. As I posted in post #119 Download the GM-Up fitter’s manual as a PDF file for your vehicle. I’m not sure how to copy a link but it is posted in post #185. Thumb through it as there is a treasure trove of information in it. The pages listed below do not have the wiring schematics but they are in different sections near the beginning of this manual. There is also a section that will show you the location of various components. Please note that I am an not a professional so double check with the up fitter’s manual. You will find wiring schematics for mirrors turn signals puddle lamps dimming etc.near the beginning of this manual. Everything works on my truck except PARK ASSIST as this would require memory option. page #280 X61A junction block panel X3 Page #297 Inside rearview mirror Page #845 Driver door harness to body harness. GOOD LUCK! P.S. 1 If you purchased different door harness say from an LTZ the reason that they are not fully functional is because most of the mirrors functions are received from the memory module. P.S.2 when you get to the correct gm-upfitter site and locate your manual, download and save it to your computer as a PDF file so you can easily breeze through the pages whenever you want.

If you downloaded the correct up fitter manual everything is there. 898 pages of electrical. I found it very beneficial to skim through the entire manual just to see how different components are wired. You will also come across the interior rearview mirror and figure out how to get the auto dim to work. Driver side turn signal Page 847. Pin #41. D-BU/WH Puddle lamp pin #3 GY/WH terminal type II. Tool J-38125-560. The mirror harness is on page 852. Driver side turn signal pin #13 type I RD/BU. Driver side puddle lamp pin #1 OG/WH. Terminal tool J-38125-553. These tools are very expensive.About $50 and $30 each. If I had to do it again I would take the donor harness to a stereo install shop and have them unpin the harness for me. Make sure to identify the correct hole in the connector before inserting the new wires. If you look closely at the connector you will see that they are numbered. Snake the new wires through the weather grommets one on body one on door before inserting the wires into the connector. Then buy the correct gripping electrical tape and cover your new wires. The dealership will not even notice your MOD. .I can't remember but I THINK the ground on the mirror harness connector is already wired for all the other functions so you should be OK as they share the ground. Once again I'am not positive about the ground as I did this mod last August and my memory is not what it once was. Follow same step for puddle lights. You will see the correct pins locations on the same page. Page 847. Good luck See my post 119 on this forum page 8 P.S. when you get to the correct gm-upfitter site and locate your manual, download and save it to your computer as a PDF file so you can easily breeze through the pages whenever you want.

From what I have read any build after August 2014 is considered 2015.5. Google 2015.5 Silverado and you can read up on that. My truck was built May 2015.

I can absolutely confirm that the above post is good information. I accomplished this in August when I first purchased my 2015.5 Lt. EVERYTHING works accept AUTO REVERSE TILT or AUTO FOLD because this would involve memory module. AUTO DIMMING works with correct rearview mirror. POWER FOLD works when button is pressed.I believe the mirror switch that I used was #23154702. GOOGLE and Download the GM UPFITTER BODY BUILDER MANUAL FOR 2015 CHEVROLET SILVERADO/GMC SIERRA ELECTRICAL SECTION PDF file. This will be your most important reference.This reference manual will also list the correct pin removal tool to use so that you will be able to remove the extra wires and pins from a donor harness. Much easier to use a donor harness than to hard wire. Everything will plug right in to the correct pin of your existing harness. I wish I could remember exactly what I did to get everything to work but just study the appropriate pages in the manual. Pg 847 is where the door harness section starts. The auto dim interior mirror has 3 extra wires Page 299.You will have to wire the 3 extra wires of the interior mirror to the X61A Junction Block - Instrument Panel X3 page 282. Pin #8 Automatic Day/Night Mirror Signal and pin #9 Automatic Day/Night Mirror Low Reference and pin#13 Backup Lamp Supply Voltage. The backup lamp voltage is what turns off the auto dim so you can see at night when backing up. One important note. I am not sure but I believe that the 2015.5 units have the new interior wiring harness.