DIY Redarc brake controller fitting

With travel restrictions still in place across much of Australia and winter set in, more than a few people stuck at home with RV rigs gathering cobwebs have been turning to DIY projects.

One electrical job that appears achievable for most caravanners is installing or upgrading an electric brake controller in their tow vehicle. Or is it?

There are a few options for controlling your caravan’s electric brakes, from hard-wired electric brake controllers (EBCs) installed in the tow vehicle to a plug-and-play loom to units fitted to the van’s A-frame and controlled via Bluetooth.

Here we’re installing a Redarc Tow Pro V3 Elite (RRP $360.50), a remote-head hard-wired controller, and the Redarc TPWKIT-013 universal wiring kit (RRP$199) on a 2001 Range Rover.

Let's get started

Redarc offers a variety of options for the Tow Pro, with two different universal wiring kits (one has a longer loom than the other, for instances where the vehicle battery is on the opposite side on the vehicle to the main wire run) and a variety of vehicle-specific wiring kits.

There are also remote head switch inserts available to give a factory-look to the install. You can also buy the Tow Pro, universal wiring kit and universal switch insert as a bundle for $526.

The Tow Pro V3 Elite has a compact main unit that fits out of sight under the dash and is operated by a remote head controller not much larger than a shirt button. It’s discreet, neat and intuitive to use.

The Tow Pro offers two modes: proportional, where the unit senses the level of braking required, or user-controlled where as the name suggests, you adjust the brake level setting according to specific requirements (such as when off-roading).

What comes in the box with the Tow Pro V3 is the main unit, the main unit pig-tail harness, the remote head controller and remote head cable. If you're replacing an existing hard-wired EBC, then this is all you will need, except perhaps a few connectors, or solder and electrical tape.

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Wiring you’ll need

If it’s a new EBC installation, then you’ll need the wires, connectors and a 30A fused link to power the unit and to feed the appropriate wires to the trailer plug. You can make up your own harness, but it’s much easier to use one of Redarc’s wiring kits, which have all the appropriate fuse and wire ratings.

The universal kit we used came with a bracket to mount the main unit, a power cable with inline fuse, a loom to run from the main unit to the trailer socket, cable ties and a variety of grommets to run wiring through an existing blanked hole in the vehicle’s firewall, for example.

This is a fairly simple job you can do yourself. Taking your time, allowing for breaks and careful review of the supplied instructions, you should have this EBC installed within a day.

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Tested: Redarc Tow-Pro Elite V3

Checks before starting install

Before starting the installation, you need to check how much wire length you’ll need between the battery and the main unit, and also how much length you need to run from the main unit to the trailer plug. Then see if you have enough space to run the harness to the rear inside the vehicle or underneath (along a chassis member, for example).

Check existing wiring harness entry points between the engine bay and cabin and, if required, between the cabin and trailer plug to run the EBC wiring. Are there blank factory holes you can use instead?

It's a legal requirement that the EBC can be operated from the driver’s seat; beyond that there are all sorts of considerations, cosmetic and practical.

Can you drill a hole for the EBC in an existing switch blank, or simply use one of Redarc’s available switch inserts in such a switch location? A popular, discreet spot to fit the head unit is on the side of the steering column -- but will the EBC switch then foul the column surround when you adjust the column reach to the forward position?

If you’ve decided to fit the switch in a trim panel that you have to drill a hole to suit, then make sure the trim is the correct thickness (between 1.25mm and 3.75mm). Wherever you decide to place the switch, make sure there’s enough space not only to fit the 31.7mm-long switch assembly behind the trim, but also the connector wire behind it (Redarc recommends 20mm space for the wire).

Last thing to check before starting is to decide on where to fit the main control unit. Unlike old school pendulum-operated proportional EBCs, the compact Redarc main unit can be fitted in any orientation, but it must be securely fixed, not flapping about under the dash.

You need to consider things such as whether there’s room for the EBC’s wire connectors to fit and if the main unit and connected wiring is likely to foul other components or moving parts.

Wiring up

Now you can begin the install, beginning with routing the power cable from the battery (do not connect it yet) to the location in the cabin where you intend to fit the main unit. Hooking a piece of steel wire (ensure there are no sharp edge on the wire) around the power wire connector, covering it in electrical tape and applying a dab of grease to the power wire will make getting it through an existing loom firewall grommet a lot easier.

If you’re running the cable to the trailer socket externally, now run the red and blue wires (fitted with connectors) on the main loom from the engine bay into the cabin.

Once you have found the best way to route the wires from the firewall to the main unit position, the red (brake light activation feed), blue (trailer brake activation) and black (power) wires can be fed into the back of the supplied connector (which already has the white earth wire attached). Insert the locking piece.

Now the main unit can be installed. We cable-tied the main unit to a fixed wiring loom enclosure under the Range’s steering column.

The earth wire terminal can now be secured, ideally at an existing earth point (as we used here in the Rangie’s right footwell) or if none are available on a bare metal structure using an existing bolt.

Fit the remote head cable and main unit wire connector to the main unit and secure with cable ties.

Fitting the remote head

We decided to fit the head unit to the right side instrument binnacle, so the binnacle was removed so that the 10mm hole could be drilled to fit the head unit. The Tow Pro instructions come with a neat template you can use (on page nine) if you want to make sure of the hole’s size and position. Drill a pilot hole first.

Now fit the remote head bezel with the level marker at the 12 o’clock position and install the remote head assembly to the trim with the remote head nut. Turn the remote head assembly shaft as far as it will turn anti-clockwise then fit the remote head knob with the ‘0’ marker on the knob aligned with the bezel level marker at the 12 o’clock position.

The main cable can now be run from the main unit to the back of the vehicle, either under chassis rails or as here, internally via the channels in the door apertures.

Wiring at the trailer socket

At the trailer socket, remove the existing red wire at terminal six and pull back outside the wiring harness. Feed this red wire into the supplied joiner (already fitted with an orange wire) and fit the rubber boot over the joiner and secure the rubber cover with electrical tape or a cable tie.

It’s time now to fit the main loom’s exposed red wire to terminal six on the trailer socket, and the main loom’s exposed blue wire to terminal five on the trailer socket.

Finally, connect the power wire to the battery and check that the system has power by pressing the remote head button (this applies manual override but for the purposes of checking that the system is live, the knob will light up).

Now all you need to do is cable-tie the EBC wiring where necessary and refit vehicle trims removed for the install.