How To Install a Brake Controller in Aurion/Camry using “Seat-Heater Power”

[Daggysheep]

How To Install a Brake Controller in Aurion/Camry using "Seat-Heater Power"

Just bought a brake controller for towing a camper trailer with electric brakes. Meant to be "plug-and-play" but it isn't and needs custom wiring.

Anyway, thought I'd have a go at installing it myself and uploading it, since the quoted install was $120-$300 (AutoBarn cheapest btw).

The brake controller electrics require power from the battery, the stoplight signal, a 20 amp fuse and an electric brake wire running from the dash to the previously Toyota installed towbar at the rear.

4 Wire diagram that I got with it for the Voyager Tekonsha brake controller is shown below:

The instructions say to locate the brake controller as far away as possible from the antenna and radio so as an added precaution to reduce RF noise I added a ferrite core to the power and brake wires as shown below to filter out noise a bit.

Using "Seat-Heater" Power

Having looked at it, I wanted to integrate it neatly into the Aurion electrics without the need for putting wires through to the engine bay directly to the battery. This avoids some fiddley work feeding loose wires through the grommet in the firewall and avoids designing in a relay, to switch off the brake controller when the car is turned off since I am paranoid it will run the battery down!

As it turns out, the Aurion/Camry Electric wiring manual is available (07EWD.pdf). This manual is separate to the service manuals.

Plenty of underutilised power is available in the junction box in the front-left passenger side behind the glove box (eg. Left Power Seat {30A}, mirror heater and seat heaters {20A}...hey, so I have an ATX!} Beautiful thing is, it is all pre-wired from the factory, and even the fuses are pre-installed so you can easily borrow power from one of these locations depending on your amperage requirements.

Anyway here's the step by step on the install, hope it helps someone...

Step 1. Prep

Assuming you have the Toyota towbar and wiring harness installed, then:

Remove the glove box and backing, left passenger foot sills, B pillar cover, front left foot cowl area cover and left cover in boot area to expose the towbar wiring harness.

Here is a picture of the junction box at the left print passenger side. While I was there I took the opportunity to clean the air conditioner filter which was surprisingly full of leaves!

Locate the thick ~2mm^2 blue electric brake wire in the boot (mine was taped back and exposed near the left rear wheel arch inside the boot.

Next unhook the negative terminal on the battery prior to any electrical work.

Step 2. Feed through the Electric Brake Wire

Attach a suitable length wire (mine was heavy gauge 12awg) to the blue electric brake wire (I soldered and covered mine in heat shrink but you could crimp it with a butt connector, blue wire would be best but I had black).

Feed the wire from the boot through to the back seat then along the left of the vehicle under the foot sills etc. to the dash. Clean up with cable ties.

Step 3. Attach Power Wire to Brake Controller

In the junction box behind the glove box locate the "seat-heater" 20A power supply no. 19 pin since we are going to use this to power the brake controller (shown in pic below). If you have higher amperage requirements an alternative would be to tap into the power seat supply - though I'm not sure this turns off when the car turns off.

Connect a wire to the power on pin 19 for the brake controller here. I searched everywhere for a proper Toyota female junction pin, I had no luck at Toyota parts or auto electricians, in the end I drilled out the plug to make space for a standard female terminal bought from Jaycar.

Step 4. Splice Stop light signal wire

Splice a wire to the stop light signal wire (blue wire in my case). I used a scotch connector for this. Connect this spliced wire to the brake controller stop light input. Picture shows connector on my job below.

Step 5. Complete the circuit

Next you want to attach the negative side of the battery to the brake controller. In most cars negative is earthed to the chassis, as it is for the Aurion. Attach the negative wire from the brake controller to a suitable earth point. In this case I chose the earth point below the junction box.

Step 6. Mount the brake controller

Couldn't find a great place for the brake controller, I put it below the steering wheel and fed the wires to it from behind the centre console.

Step7. Check Fuse and Relabel.

The fuse for the seat-heater is under the junction box we have been using. Check it is installed should be a 20A micro-blade fuse shown below. I relabeled mine so I can find it if the brake controller blows....

Final Step.

Reconnect negative terminal of battery, then do whatever you manual says to calibrate/tune the brake controller.

You're done! Get the kids to cleanup and reassemble the car while you relax.....argh!

[ColTil]

I have an Aurion Sportivo SX6 and the junction box/fuse appears to be different to the photos you have posted. Any ideas were I can get details for my vehicle.

With thanks

Colin

[bearj]

hey, I realize I am not helping with your post but it prompted me to ask a dumb woman question, I have a 2007 pressara aqnd love it but would have loved it more if it had come with heated seats as I have lower back issues. Does anyone kniouw if it is possible to have heated seats and how to go about it if you can. Thanks Bear

[Roughasguts]

Im pretty sure when I wired up my electric brakes with a prodigy controller! they asked for a 20 Amp Auto resetting circuit breaker! straight from the battery for obvious reasons.

Mine is installed on the fire wall, only $10.00.

Cheers.

[CONROD]

Im pretty sure when I wired up my electric brakes with a prodigy controller! they asked for a 20 Amp Auto resetting circuit breaker! straight from the battery for obvious reasons.

Mine is installed on the fire wall, only $10.00.

Cheers.

That is correct power from the battery has to come directly from the battery NOT be via ignition for reasons relating to if for some reason the fuse blows etc the trailer/van will not have any braking due to the controller not having any power. And it has to have a THERMAL CIRCUIT BREAKER NOT a FUSE.

Roughasguts has had it carried out correctly