Brake Controllers & LR4

Robert Kinsler said:

I just snagged the controller from British Atlantic along with the trailer wire harness and an ox hitch.

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Nice haul! You’ll be set. Make sure you’ve got access to a good torque wrench for installing the Rhino (aka Ox) hitch.

Re the trailer harness, fitting the interface into the cutout in the bumper takes some finagling. Just as you start getting irritated, it will slip into place like a puzzle piece. Be patient. I also had to undo some of the black electrical tape to expose more of the grounding wire so it would reach its connection point in the side panel of the cargo area (retape the bundle after you pull out more grounding cable). Otherwise a straightforward and satisfying project.

Thanks for those tips. Planning to knock this out with a buddy of mine who has the tools when they all come in.

For the brake controller, is that just a nice to have or a must have? Meaning does the lr4 have some basic control of the trailer you don't upgrade in this way?

Robert Kinsler said:

Thanks for those tips. Planning to knock this out with a buddy of mine who has the tools when they all come in.

For the brake controller, is that just a nice to have or a must have? Meaning does the lr4 have some basic control of the trailer you don't upgrade in this way?

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If your trailer has electronic brakes you need a brake controller.

Do trailer brake controllers generally send +12V to the brake switch line (pin 5 of the Ford connector) when manually activated? I'd expect this to backfeed into the BCM and ECM, and from reading install instructions it seems the Redarc Tow-Pro controller does this:

The requirements for a suitable connection of a brake controller trigger wire are specific. This connection point must:
• Provide a voltage of the same voltage level as the Start Battery* while the vehicle brakes are applied.
• Have 0 volts output while the vehicle brakes are not applied.
• Accept battery voltage input when the brake controller manual over-ride is operated and illuminate at least the trailer brake lights.
• Accept the battery voltage input as above without causing any damage, spurious vehicle operation or erroneous fault indication.

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The last two bullets I think would be problematic if the car was off and the trailer brakes manually applied. Does the Tekonsha P3 do this too? I couldn't find any useful information on their site about whether the brake line used as signal (input) only by the controller, or if it also sends power out that way during manual application of trailer brakes.

I believe the Tekonsha P3 would do the same thing - energize the brake line signal, even when the car is off. I did a bit of probing with the multimeter today, and the brake pedal switch gets constant +12V, not switched. I checked pin 5 of the trailer brake controller plug, and it indeed shows +12V when the pedal is depressed, even if the car is off. So it's safe for that wire to be energized by the brake controller - it's no different than pressing the brake pedal when the car is off. The thing that threw me off is discussions about folks in Australia having to fit a diode, and folks with a D3 having ECUs power up when manually activating the trailer brakes with the car off. The OEM fitted Ford connector for trailer brake controller sure is a nice feature.

I have an '16 LR4 and P3 controller.

Seems like best place to mount is below small vent to left of start button.

I thought I would be able to get double sided tape to work. But not so.

How and where have y'all mounted?

I got the RedArc controller, and it tucks in behind the lower panel under the steering wheel. There's a rectangular cutout to the left side of it that is a perfect size to hold it securely. Completely out of sight, except for the control button which for now is velcro-taped to the steering column. I plan on moving it to the headlight switch area but haven't gotten around to it.

The P3 is a controller with emergency slider, which seems to offer easier control whilst emergency braking.