Comparing Supplemental Brake Systems

A supplemental brake system is a good idea when towing a car behind your motorhome. required depending on the weight of your dinghy. We compare options such as the US Gear Unified Tow Brake.

Supplemental Brake Systems

When we purchased a Saturn as our tow car, we also wanted to get a new supplemental brake system.
Jose did his research and comparison, and has the following comments on this project.

Since we had previously had a towed vehicle brake system, I had some idea what I wanted.  
Specifically, I was looking for the following features:

  • Hardwired audible and visual breakaway notification
  • Hardwired indicator when supplemental brake system in towed vehicle was employed
  • Warning if towed vehicle’s brake system was activated while the motorhome brakes were not.
  • Easy setup for towing
  • Tow vehicle braking adjustable from the motor home
  • No bulky boxes between the brake and driver’s seat
  • Installable by a backyard mechanic (me)

I found a website with an unbiased
comparison of supplemental brake systems
that I used to narrow down which brake systems were to be considered.

The US Gear Unified Tow Brake system was the only one (at the time) to
have all of the features I most wanted. Most important was a hardwired
audible and visual “brakes applied” and breakaway notification.

Our prior supplemental brake system relied on a wireless sending
and receiving unit to inform us when the towed vehicle’s brakes were
engaged or there was a breakaway. I had zero confidence in its
ability to accurately display what was happening with the towed
vehicle’s brakes. All too often, it would give false readings,
especially when no brakes were applied. An additional shortfall was
that it did not have an audible alarm for a breakaway or if the towed
vehicle’s brakes activated when the motorhome brakes were not engaged.

First impressions – parts and pieces:
Everything that the manufacturer provided was of good quality and well-packaged. The US Gear Unified Tow Brake
parts were clearly labeled and/or the instruction sheets showed a
picture of the part and where it was supposed to go in the assembly.

The instruction booklet was easy to read, with instructions in a
logical sequence. Accompanying illustrations were clear and
to-the-point. Also included was an instructional video CD and a
telephone hotline. I used all of the material with good success. This
is a very complete package that includes everything needed for
straightforward installations.

Installation impressions:
This supplemental brake system can be installed by a backyard mechanic
if you have the time and the patience. Even though the instructions
provided were straightforward and easy to follow, it took me about four
days worth of effort to do this myself. I imagine most of you
reading this will think that I am a slow poke… but there it is.

Tools used:
Drill, drill bits, ratchet, sockets, wrenches, screwdrivers, sharp utility knife, electrical tape, patience (lots of patience).

Installation in the Towed Vehicle:

The most difficult, time consuming and frustrating aspect of the
installation was attaching a pulley to the firewall behind the brake
pedal and getting the actuator cable to pull in a straight line. In
my Saturn (2003 L300) there are no flat areas either directly behind or
slightly lateral of the brake pedal.

Once I picked a spot for the pulley and fabricated a mounting
block, I knew I would have difficulties with the actuator cable lineup.
The actuator cable is attached to the brake pedal via a bolt-on
clamp, but was too far to the right to line up with the pulley. So
once again, I given the opportunity to think out of the box and
fabricate an offset to get the cable to line up with the pulley.

Once I was able to attach the pulley, the rest of the
supplemental brake installation was easier. Notice I said easier, NOT
FASTER… I am still slow.

Installation in the Motorhome:  
By far, this was the easiest part of the installation. The only
problem I encountered was finding a wire route from the back of the
coach to the front, for the connections to the Unified Tow Brake
controller. I solved this by contacting the coach manufacturer and
getting them to identify a spare wire that ran where I needed it.

I was stumped for a short while trying to find the “Brake Pedal
Switch” until it dawned on me that I would not find it by the brake
pedal under the dash. My coach has air brakes so the lines and the
air brake switches are in a compartment under the floor and below the
drivers seat.

Impressions after 40,000 miles:   
The US Gear Unified Tow Brake system has worked exactly as
advertised. I keep it set to its lowest sensitivity setting. I am
much more confident in this supplemental brake system than what I used
in the past.

If you are wondering if I can feel it when the towed vehicle’s
brakes come on, all I can say is “No”.    My motor home weighs close to
40,000 lbs., the car weighs about 3,000 lbs. I wouldn’t expect to
feel it.   However, being curious myself, I put Jill in the towed vehicle
to check things out on a short test drive, and it is working as

I will soon be reinstalling it in a new tow vehicle.  Will let you know if there is any change to how it performs with the new car.