Factory integrated brake controller not recognizing trailer.

dkad260

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2012 XL Denali with OE controller, will not display the trailer is connected, I tested this on a 2nd trailer also.

Trailer lights, signals, and brake lights work, no corrosion on either side of the 7-pin connector.

I removed the kick panel and the controller is connected, also the controller illuminates when headlights are on.

I do have the JL1 RPO code

Fuse #6 is good.

No codes

Pressing the +/- buttons or sliding the lever does not display anything.

Would the relay cause this?
 
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dkad260

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Ok, I double checked under the hood, I see a red wire wrapped up outside a wire loom with a ring terminal. I'm assuming that's our mystery GM red wire.
 

swathdiver

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2012 XL Denali with OE controller, will not display the trailer is connected, I tested this on a 2nd trailer also.

Trailer lights, signals, and brake lights work, no corrosion on either side of the 7-pin connector.

I removed the kick panel and the controller is connected, also the controller illuminates when headlights are on.

I do have the JL1 RPO code

Fuse #6 is good.

No codes

Pressing the +/- buttons or sliding the lever does not display anything.

Would the relay cause this?
If anything is amiss with the trailer brake system it will not connect to anything. If everything checks out, it is possible that the trailer's type of brake system is not compatible.

Reading this again, are you saying that if you move the slider nothing appears on your DIC? It ought to.

The SSR is located right behind the ABS pump. Do you have a bi-directional scan tool to pull chassis codes? That's where the ITBC resides.
 

swathdiver

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Ok, I double checked under the hood, I see a red wire wrapped up outside a wire loom with a ring terminal. I'm assuming that's our mystery GM red wire.
Hold, on, was this under the brake booster or alongside the fender? If you have JL1, this should have been connected already. Do not connect if an aftermarket controller is attached with the wires from under the dash.
 
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dkad260

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Hold, on, was this under the brake booster or alongside the fender? If you have JL1, this should have been connected already. Do not connect if an aftermarket controller is attached with the wires from under the dash.

I don't have an aftermarket controller, only the original factory integrated.

This is the red wire outside the fuse box on the fender.

Screenshot_20220801-014032_Gallery.jpg
 

swathdiver

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I don't have an aftermarket controller, only the original factory integrated.

This is the red wire outside the fuse box on the fender.

View attachment 376885

OK, that gets connected to the left terminal and you'll be all set then. If you want power to the inside the trailer, the other bundle of wires under the brake booster gets connected to the right terminal. Remember though, even when the truck is off, it is powering the trailer's interior with that wire connected.
 

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OK, that gets connected to the left terminal and you'll be all set then. If you want power to the inside the trailer, the other bundle of wires under the brake booster gets connected to the right terminal. Remember though, even when the truck is off, it is powering the trailer's interior with that wire connected.

What do you mean by "left" terminal? The one on the driver's side, or the one on the left as viewed from the front of the truck?
 
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The terminal posts are different size and so are the ring connectors on the ends of the wires and they'll only go on the corresponding terminal post.

When looking at the engine, the wire bundle on the right (between fender and fuse box) goes to the left terminal post, and the wire bundle on the left (under brake booster) goes to the right terminal post.
 
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dkad260

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Ok, so the wire I pictured was under the brake booster, there is another tucked away next to the fender...that one has the larger terminal.

The pic shows that the larger wire is for an "aftermarket" controller. Is that still the one for the factory ccontroller? I assume not.
 

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