Battery charge wire and brake control wire 2012 Yukon

[scot moore]

Hi just looking for confirmation on the locations of these 2 wires. I have this diagram, but I was expecting the battery charge cable to be on the same side as the battery charge post, and I was expecting it to be the larger of the 2 posts



On that image the wire location labeled battery charge goes to the smaller post on the right, and the brake control wire goes to the larger post on the left. I was going to take a dmm and test the connections on my 7 pin connector, but figured this has been dealt with a lot on here. I did not see any post discussing it though when I searched. Thanks


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[kbuskill]

Hi just looking for confirmation on the locations of these 2 wires. I have this diagram, but I was expecting the battery charge cable to be on the same side as the battery charge post, and I was expecting it to be the larger of the 2 posts



On that image the wire location labeled battery charge goes to the smaller post on the right, and the brake control wire goes to the larger post on the left. I was going to take a dmm and test the connections on my 7 pin connector, but figured this has been dealt with a lot on here. I did not see any post discussing it though when I searched. Thanks


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The battery charge terminal and wiring doesn't need to be real heavy duty as it is just charging the trailer's backup battery for the break away safety switch so it doesn't have a large amperage draw.

As a side note the wires have different size lugs on them and will only fit on the posts they are supposed to be on.

 

[scot moore]

Thanks, I do understand what you are saying, and mine do only fit one way, unless you were to put the larger terminal on the smaller lug... the thing I am really trying to figure out is if I currently only have the brake control wire hooked up, or If I do in-fact have the 12v charge wire hooked up. Weather is bad here so I didn’t really want to go out and check with the dmm. I did find a diagram on etrailer and they also show the battery charge wire on the left side, but the show it connected to the left post. Both of my wires are the same color, and they are both where the picture shows. Just trying to confirm for sure which wire is which. Thanks!


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[PG01]

Thanks, I do understand what you are saying, and mine do only fit one way, unless you were to put the larger terminal on the smaller lug... the thing I am really trying to figure out is if I currently only have the brake control wire hooked up, or If I do in-fact have the 12v charge wire hooked up. Weather is bad here so I didn’t really want to go out and check with the dmm. I did find a diagram on etrailer and they also show the battery charge wire on the left side, but the show it connected to the left post. Both of my wires are the same color, and they are both where the picture shows. Just trying to confirm for sure which wire is which. Thanks!


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Battery charge wire, red with black strip iirc, is down under master cylinder (which you already know) and connects to right post looking at the fuse box when standing in front of truck and looking under hood. The brake controller wire, red, is in between fuse box and fender (which you already know) and connects to left post when standing in front. If there is a factory controller in the truck a red wire will be on left post already. you need a 40a jcase fuse for the battery charge/right post. Hopefully you figured it out already but if not hope this helps you out.

 

[swathdiver]

AllDataDIY has the GM write up on this too. I have the integrated trailer brake controller, JL1, and do not think I have to do anything on mine. I did notice however, that the red wire with the black stripe is on the left, larger post. I do not see a red wire either but maybe didn't look hard enough.

 

[PG01]

AllDataDIY has the GM write up on this too. I have the integrated trailer brake controller, JL1, and do not think I have to do anything on mine. I did notice however, that the red wire with the black stripe is on the left, larger post. I do not see a red wire either but maybe didn't look hard enough.

Right, factory integrated controller is all ready to go.
No factory controller and you need to hook up at a minimum the wire in between fender and fuse box to tge left post.. Both are red and have a black stripe....iirc

And i missed a period in my top post

 

[swathdiver]

My red wire with black stripe that attaches to the larger left post comes from under the master cylinder.

 

[PG01]

It looks like it does but it goes into a wireloom thru the firewall to the integrated controller. If you look youll see one coiled up and taped under the master too. Also one coiled and taped next to the fuse block by fender. For some reason gm ran wires even if you have an integrated controller.
To be honest and iirc even with our integrated controllers if we want battery power/charging capability we have to hook up the one under the master to the right lug but we have a jcase fuse already.

 

[swathdiver]

Ok, I'll look tomorrow.

 

[scot moore]

Thanks for the help. Here is what I have found out from searching. It looks like the 2 wires are always the same color. It also looks like the brake control wire is always between the fuse block and fender. It looks like the 12 v charge wire is always under the master cylinder. However in different years, production months or models sometimes the 12v power hooks on the big post on the left, sometimes it hooks to the smaller one on the right. All of the pictures of Yukons I can find show it is the big post on the (left) but mine is not, and I have read some others are not either. On the Sierra, it looks like they hook the way mine do. I saw a diagram that was exactly like mine. I have also tested mine with a ddm and it is correct.

(Meant big post on left)


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