I just finished my install today based off of install by @tha_lildude.
First of all my truck is a 2016 3500HD Duramax with Work Truck convenience package so I know this is the wrong sub-forum I'm posting in but it might still be similar for other trucks.
Parts list for my application:
AUX switch for LML Duramax. #23145163 [TC / Cargo / Exhaust Brake / AUX 1 /AUX 2 / AUX 3 / AUX 4]
Wire 4 pieces #19301761 (load carrying) (big wire)
Wire 8 pieces #19301767 (control) (small wire)
GMUpfitter says to use Connector #19328970 and wire #13578892 and wire #1357583. My finds are you don't need these part number unless you intend to control the loads that are installed inside the cab of the truck. If all your loads are going to be installed outside (lights, air compressor, beacons) then save some money.
I read the 2016 SIlverado/Sierra Electrical book and found the correct wire/terminals. I also found where each wire is supposed to go.
Okay, from the top.
S48A is the block number for the switch panel located below the AC controls.
X61A is the block located in the driver foot well by the parking brake.
X50A is the underhood fuse block located on driver side behind the battery.
My truck had the wiring between S48A to X61A. You can verify the wires are there by removing cover for X61A and checking connector X5. X5 is white connector on bottom right.
The pins you are looking for are:
10 RED/WH
17 YELLOW/WH
11 L-GREEN/WH
23 WH/D-BLUE
After you verify those are there I believe the next step is where the 9L7 rpo code changes things.
My truck didn't come with the wires between X61A connector X1 and X50A connectors X3, X5. The control wire I mentioned above will go here. #19301767.
X61A connector X1 is located on the back of X61A. Remove 3 10mm nuts and turn it over. Connector X1 is the lower of the 2 on the back. You need 4 pieces of #19301767 wire.
Those wires need to be inserted into the X1 connector.
Remove X1 connector from X61A block.
Remove terminal hold down cover (blue thing opposite wires)( prevents terminals from pulling out and being put in.)
Insert wire to :
21 RED/WH
34 YELLOW/WH
30 L-GREEN/WH
38 WH/D-BLUE
reinstall terminal hold down cover for X1.
Next you need to verify you have the right fuse block X50A. According to tha_lildude, his truck didn't have the male terminals under his fuse block. When I pulled my fuse block I found out that I have all the proper male terminals under the fuse block. I am not sure what model options or trim levels will affect this but my truck is a 3500HD WT Duramax. My X50A underhood fuse block part number is #23285571.
Tip: remove the HORN fuse so you can reinstall the fuse block in peace, the truck alarm will sound when you plug the fuse block back in.
Remove X50A fuse block by flipping the 2 levers and pulling straight up.
Remove 13mm nut from battery cable to fuse block.
X4 is the connector in the middle toward rear of truck.(where the battery cable went). X3 should be the connector closest to driver fender toward rear of truck. When looking at fuse block side or connector side you need to remember what position you are looking at it from. Need to think upside down.
On the X4 section of the fuse block you need to see if the following male terminals are there. The fuse block has letters and numbers cast into the plastic so it should be easy.
G2 big terminal
L6 small terminal
K5 big terminal
L1 small terminal
K2 big terminal
On the X3 section of the fuse block you need to see if the following male terminals are there
M5 small terminal
M7 big terminal
F3 small terminal
Once you check the fuse block side you can install the wires that will connect to X61A.
Press tab and slide X4 connector out. Remove back cover. Remove blue terminal hold down cover. The back of the connector also has numbers and letters cast into the plastic but they're small so bring a magnifying glass or something. You need 3 pieces of #19301761 wire and 2 pieces of #19301767 wire. Insert the wire into the following:
G2 GREY/BLACK (big wire)
L6 L-GREEN/WH (small wire)
K5 YELLOW/BROWN (big wire)
L1 WH/D-BLUE (small wire)
K5 RED/L-GREEN (big wire)
Reassemble X4 connector and reinstall.
Press tab and slide X3 connector out. Remove back cover. Remove blue terminal hold down cover. The back of the connector also has numbers and letters cast into the plastic but they're small so bring a magnifying glass or something. You need 1 pieces of #19301761 wire and 2 pieces of #19301767 wire. Insert the wire into the following:
M5 RED/WH (small wire)
M7 D-BLUE (big wire)
F3 YELLOW/WH (small wire)
Reassemble X3 connector and reinstall.
Take 4 small wires coming from X50A fuse block and match them with the 4 small wires from X61A
4 big wires coming from X50A will go to power your loads.
Wiring diagrams are from 2016 Silverado/Sierra Electrical Manual found on GM Upfitters. Important pages are
530
538
541
576
577
Also UI Bulletin #110L from Gm Upfitters is helpful.
