How to Identify Connectors

[LifeLongWNYer]

Hi folks.  I have a 2015 Sierra and am getting ready to make a couple of additions and changes to it.  I have been reading the posts about how to do most of them, and i "think" I'm okay, at least, so far, I am, but I do have one question. 

 

How do I identify the various connectors at the underhood fuse panel and the panel behind the brake pedal on the inside of the firewall?  Many of the helpful posts say to splice into "wire 12 on connector x1" but I can't find which of the connectors is "X1".  I have downloaded several of the manuals from GM, and see that they also refer to a spoecific wire in a specific connector, sometimes even showing a picture of the connector, but I can't figure out how to determine which connector goes by which name.

 

 

Thanks,

 

JBP

 

 

[Racindave]

What are you trying to hook up? I’d stay away from splicing if at all possible. Use add a circuits and tap into the fuse boxes. 

[davester]

get a subscription to the full-service manual for your truck.  It details what each pin on every connector is for, wiring colors, wiring diagrams, everything you would need for this.  I highly recommend it, particularly if you are going to keep the truck for some time and you want to diagnose or repair problems with your truck.

[LifeLongWNYer]

first to RacinDave.... I have to add a trailer connector wired to the ATA scheme, in that the turn signals are separate from the stop light circuits.  I have been told to rewire the trailer, BUT I have several trailers and several other trucks, ALL wired to the ATA standard.  I will be easier to rewire the GMC, then to redo all the others.

 

Now to Davester:  I have several downloaded manuals, as well at the GM Upfitters manual.  I have my issue sorted out, I will splice into the feed wire to the front turn signals and run a wire from each to the trailer connector.  From the manuals, I know which wires I need, but all the manuals tell me to find those wires in connector X1 at the left front fender fuse panel.  What I can't find anywhere is which of the five connectors on that panel is the "X1" connector.

 

I am certain that GM marks the connectors somehow, but can't find any such documentation.  I think maybe GM presumes that "everyone knows", but I assure you, I don't.

 

Thanks for the help guys, I appreciate your experience and time.

 

JBP

[davester]

I don't know about the specific connectors you are talking about, but for my truck, GM color coded the plugs when there are multiple connectors in a row that are the same style (for example, the BCM in the cab, and the plugs at the back for the taillights), and the FSM has the color of the connector as part of the pinout description for each of them.

[tbarn]

fuse box.pdf

[tbarn]

X1.pdf

FYI, these terminals are very easily damaged. Try not to twist and turn the connector while removing it. And DO NOT jamb a test light into the terminal.

 

Pin	Size	Color	Circuit	Function	Terminal Type ID	Option
A1 - B1	—	—	—	Not Occupied	—	—
B2	4	RD/GY	642	Battery Positive Voltage	I	1500
C1 - C3	—	—	—	Not Occupied	—	—
D1	0.75	YE	712	Left Headlamp Low Beam Control	III	—
D2	—	—	—	Not Occupied	—	—
D3	0.75	L-GN/PU	1315	Right Front Turn Signal Lamp Control	III	—
E1	—	—	—	Not Occupied	—	—
E2	4	RD/WH	342	Battery Positive Voltage	I	1500
F1	0.5	GY/BN	309	Right Park Lamp Control	III	—
F2	0.75	GY/VT	228	Windshield Washer Pump Control	II	—
F3	0.75	D-BU/WH	1314	Left Front Turn Signal Lamp Control	III	—
G1	0.5	VT/GY	709	Left Park Lamp Control	III	—
G2 - G3	—	—	—	Not Occupied	—	—
G4	0.5	BK	150	Ground	II	—
G5 - H1	—	—	—	Not Occupied	—	—
H2	0.75	GY/D-BU	7538	Left Front DRL Control	II	Z88 with SLT
H3	—	—	—	Not Occupied	—	—
H4	0.5	WH	311	Right Headlamp High Beam Control	II	—
H5	—	—	—	Not Occupied	—	—
H6	0.75	D-BU/BN	7539	Right Front DRL Control	III	Z88 with SLT
J1	—	—	—	Not Occupied	—	—
J2	0.75	BN/GY	29	Horn Control	II	—
J3	0.5	BN/VT	2234	Front Fog Lamp Control	II	T3U
J4	0.5	WH	711	Left Headlamp High Beam Control	II	—
J5	0.75	YE	312	Right Headlamp Low Beam Control	II	—
J6 - N2	—	—	—	Not Occupied

[LifeLongWNYer]

Thanks Davester, I have several pdf"s which I've downloaded and never found anything about the connectors being color-coded.  Can you help me by telling me what colors the connectors are on the underhood fuse panel? 

 

...or, if I am looking down at the underhood fuse panel, while it is mounted, which connector is which?  I am set, I think, with the wires that i need and which colors THEY are, but just don't know which connector they appear in.

 

 

Thanks for the help,

 

JBP

 

 

[tbarn]

1 brown

2 green

3 gray

4 black

5 natural/neutral

[LifeLongWNYer]

BEAUTIFUL, TBarn, I think that will help me quite a bit.  Thank you!!!

 

 

JBP