Installing aftermarket brake controller with factory ITBC (JL1)

[dkad260]

I'll check this tomorrow, but this mystery relay under the brake booster, might be part of this puzzle.

 

[gooffeyguy]

I'll check this tomorrow, but this mystery relay under the brake booster, might be part of this puzzle.

View attachment 377618

View attachment 377619

I have that relay on mine (no JL1 or ITBC) and connected that wire to the driver's side stud in front of the box. The wire that's between the box and fender I connected to the passenger side stud. I did this when I wired my aftermarket brake controller.

 

[gooffeyguy]

That blue wire under the dash is the brake control coming from a connected brake controller back to the 7 pin trailer plug.

On another note, the manual says that the ITBC will not connect to a trailer if there are any problems or DTCs in the brake, antilock, or stabilitrack systems.....

 

[dkad260]

That blue wire under the dash is the brake control coming from a connected brake controller back to the 7 pin trailer plug.

On another note, the manual says that the ITBC will not connect to a trailer if there are any problems or DTCs in the brake, antilock, or stabilitrack systems.....

Copy that....so I assume that the blue from the relay has to be tied into the blue under the dash in some form or fashion. I'm just trying to fully understand the system so bear with me.

I get the basics of the wiring, but not this JL1 setup.

@swathdiver did touch on the part about the codes. Problem is, I see there's a fault, but no codes are set.

 

[Fless]

Are you using a scanner that can read body, ABS, and non-powertrain codes?

 

[dkad260]

Are you using a scanner that can read body, ABS, and non-powertrain codes?

Yes, using a Tech 2.

 

[swathdiver]

That blue wire is referred to as D-BU in this diagram.

I am concerned about the notation in Tom's earlier post that says the blunt wires are disconnected further up in the wiring harness when a vehicle is equipped with JL1. There was a guy on here that fried his when he connected both.

Did you run a master scan across all modules at once for trouble codes?

 

[swathdiver]

Came across this slightly different diagram a few minutes ago. It's from the 2013 Upfitter's Electrical Manual.

 

[dkad260]

I will run a scan on all the modules.


Looking at the 2nd schematic, this looks like it's a junction and should play nicely....unless I'm reading this incorrectly.

 

[swathdiver]

I just went out to my truck and don't have that loose relay. I suspect that is part of your problem if it doesn't belong there.

@gpracer1 @Matthew Snyder

Do you guys have that relay around your brake booster as in Post #11? I don't but wanted to double check with those that have newer vehicles.