Trailer Brake Controllers: What's Wrong and What's Right


There are two things to know if you’re going to tow a trailer: Towing is never a trivial matter, and you can never have too much brakes. If you can't pull a trailer over a hill because you don’t have enough power, that’s an inconvenience. If your brakes fail coming down, that’s a disaster.

Generally, when towing a trailer that weighs more than 3,000 pounds, I highly recommend having trailer brakes separate from the truck you’re towing with. There are two types of trailer brakes: surge and electric. Surge brakes work independently from a truck, when forward momentum caused by deceleration hydraulically applies the trailer brakes as the truck slows. The greater the trailer’s forward momentum against the truck, the more brake pressure is applied.

Electric brakes, on the other hand, work in tandem with a truck’s brakes. They’re connected directly to a truck’s brake system via a brake controller inside the truck, so that when a driver applies the brakes, the trailer brakes are applied at the same time. Some electric trailer-brake controllers can be actuated manually by the driver, allowing the trailer’s brakes to be applied independent of the truck’s.

An aftermarket trailer brake controller, like this model from BrakeSmart, can be placed almost anywhere the driver likes in the cabin. It provides proportional trailer brake response in relation to the tow vehicles' brakes by using a pressure sensor thatmeasures the output pressure of a tow vehicle.

While trailer-brake controllers have typically belonged to the aftermarket realm, automakers are starting to get in on the act with some interesting changes for long-time trailer-towers used to choosing what kind of unit to purchase and where to position it in the cabin.

Here are some manufacturing milestones on this front:

Ford, 2005: It was a safety breakthrough when Ford introduced the first integrated, factory-installed trailer-brake controller in the 2005 Super Duty. The Ford TowCommand proportional trailer-brake controller, manufactured by Tekonsha, ties into the truck’s hydraulic brake line to activate the trailer brakes by sensing truck-brake pressure. It can apply the trailer brakes as fast as the truck brakes. Before ABS came to trucks in the ‘80s, most trailer-brake controllers worked this way, activated by the truck’s hydraulic brake action. In an emergency situation, with the truck’s ABS activated, Ford's TowCommand can reduce trailer-brake pressure (or gain) as it communicates with the truck's computer for faster reaction times with proportional trailer-brake control, to prevent the trailer brakes from locking up. Ford put its TowCommand on the right side of the steering column, which is where semi-truck cabs put their long trailer-brake levers. Tekonsha also makes the Prodigy aftermarket trailer-brake controller. This year, Ford offers TowCommand in the 2009 F-150.

GM, 2007: GM comes in second, offering a factory trailer-brake controller option in 2007 on the new GMT900-platform trucks and a factory-integrated controller in the HD2500/3500 trucks. Continental, a vendor know for making electronic stability systems, makes the proportional, electricity-activated brake controller for GM trucks. Today, GM also offers a built-in trailer-brake controller on 2009 half-ton trucks. Like Ford’s, when activated, the truck’s ABS brakes reduce gain to the trailer brakes. In GM trucks, however, the controller gain adjustment and hand control are on the left side of the steering column. It's all electronic, not hydraulic, like Ford’s TowCommand.

Dodge, 2010:  For the 2010 model year, Dodge light and heavy-duty trucks will have available integrated trailer-brake controls. Trailer-brake control information will be displayed in the Ram’s Electronic Vehicle Information Center, which is standard on diesel models and available on gas SLT, TRX and Laramie models. filmed the at the Chicago auto show with the factory trailer-brake controller positioned on the left side of the driver.

Factory trailer brake controllers are available in current GM and Ford trucks and in Dodge Ram (pictured) pickups starting in 2010. The Ford and GM units are supplied by well-known aftermarket trailer brake companies but are purpose-built to work with the particular trucks' brake system. They have a refined appearance but are only installed in a specific place in the truck regardless of driver preferences.

As great as these manufacturer solutions to trailer-brake situations are, GM’s and Dodge’s placement of the controllers concerns me. Perhaps some folks will react quickly to a brake controller on the left side of the steering column, but the majority of us react faster to a controller on the right side of the steering column. That’s why the long trailer-brake lever on a semi-truck is on the right side.

I spoke recently at an Air Stream RV trailer rally in Colorado about trailer safety. I asked the towing group of Air Stream owners if any of them had their trailer-brake controller on the left side of the steering column. No hands went up. I asked a GM engineer why that company puts the trailer-brake controller on the left side in its trucks, and the answer was that it’s easier, and there’s more room in the dash to locate the controller on the left side. While reviewing the all-new 2009 Dodge Ram last year in's  , I asked a Dodge engineer where the company put the trailer-brake controller in 2010 trucks and was again told it was easier to locate the controller on the left side.

The placement of these controllers presents an interesting safety issue. When your trailer is out of control and you need to grab just the trailer-brake controller, not the foot brake, with just seconds to avoid a tragedy, do you have the dexterity to do so with your left hand without taking your eyes off the road?

Factory trailer brake controllers can display key messages in a trucks' driver information center. Aftermarket units may only display important notices in the brake controller itself, if at all depending on price.

Does it really matter? I think so, and my opinions come from hard-earned experience. I routinely tow heavy trailers across the country with my heavy-duty, five-speed manual pickup. Maintaining control over the trailer brakes helps keep me alive.

A 250-mile trip on I-70 through the Rockies in January with a gooseneck horse trailer really tested my trailer-braking skills using a controller manually. I slid on ice-covered asphalt even though the combined weight of my truck and trailer was well over 10,000 pounds. If I accelerated too quickly, the trucks’ rear tires would break loose and shift the truck sideways. Seven percent grades out of the Eisenhower Tunnel and Vail Pass in Colorado had me controlling my descent on curves with the trailer brakes only, using my aftermarket trailer-brake controller.

Until antilock brakes are available for trailers, if you’re on slick surfaces or in a trailer sway situation, you’ll likely need to apply the trailer brakes for control. Without an engine exhaust brake, a manual transmission going downhill can push engine RPMs against the redline if you don’t use the brakes some. Applying the trailer brakes first and then both for extra stopping power can be a safer choice.

I know people who have rolled their truck and trailer because they didn’t know to apply the trailer brakes first with a trailer-brake controller in a sway situation. It’s especially critical with conventional trailers, where the tongue weight of a trailer is behind the rear axle of the tow vehicle. Trailer sway can be magnified, and leaf springs on the trailer create so much momentum you can't control your rig. Over-the-road truckers know to grab the trailer-brake handle and hit the throttle to bring a trailer under control.

Truckers know to use the trailer brakes separately in bad weather and on winding roads, when the trailer wants to pass you. Generally, gooseneck trailers, with their tongue weight closer to the center of your pickup truck, sway less but can also try to jackknife on slippery roads. Speaking from experience, I jackknifed my flatbed gooseneck on a snow-drifted dirt road. The trailer brakes didn't work, so all I could do was watch my trailer, as if in slow motion, swing around and take out the driver’s side mirror and window. I've learned the hard way how important it is to have good trailer brakes and be able to quickly, safely brake the trailer independently.

Suffice to say, this is an issue manufacturers need to get right.

Of the three OEM optional factory trailer brake controllers, we prefer Ford's placement on the right-hand side of the driver.


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