[Bill]

Well, I missed this thread while we were crossing the country in our TM. Oilspot asked about experiences with brake controllers. Let me add my two cents worth.

There are basically three types of controllers. The first, and cheapest, is a time-cycle controller. I started my TM experience with one of these, and hated it. It is also unsafe, in my opinion. It connects to the brake light wire so that it knows when you are braking, but it doesn't know how hard you are braking. Instead, it just starts out braking the trailer gently, and then gradually increases the brake current. Needless to say, this is NOT what you want in a panic stop situation. The operative expression is "They work just fine when you don't need them."

The second (and most common) type is the inertia controller. It has a small weight suspended somehow in the controller - think of a pendulum. When you apply the brakes and begin to decelerate, the weight moves away from its rest position. The harder you decelerate, the further the weight moves. The amount of movement sets the amount of current sent to the brakes. You set it up so that the weight hangs straight down (rest position) when the car is level. If the controller is mounted at an angle on the dash, there is a compensation step so that it "knows" where the rest position is. The drawback is that simply going downhill moves the weight away from the rest position, so even if you apply the brakes gently, you may get more trailer braking than you wanted. On a steep hill, the trailer ends up doing more than its share of braking.

The third type, and to me the best by a wide margin, is called "full proportional". It actually measures the position of the brake pedal, and translates that directly into trailer braking. If you push the brake pedal a little, it instantly gives you a little trailer braking. If you depress the brake pedal further, it instantly gives you more trailer braking. Uphill, downhill or at rest, it doesn't matter - it just measures the position of the brake pedal, and applies that amount of trailer braking. In the old days (the 60's, maybe), all controllers were built this way. They tapped into the hydraulic braking system to measure how hard you were pushing the pedal. For many reasons, you can't do this on modern hydraulic brake systems, so the time-cycle and inertia controllers were invented as a way around the problem. Neither is as good as the old hydraulic system. But there is at least one controller out there does the same thing as the old hydraulic system. It is activated by a short piece of steel cable that is attached to the brake pedal arm, up behind the dash and out of the way. When you push the brake pedal, the cable pulls a slider in the controller, and so you get instant and exactly proportional response. I love it, and more importantly, I feel safe with it.

As an aside, the time-cycle controllers and inertia controllers both connect to your brakelight wire - that's how they know when you are braking. And that works reasonably well, provided that the brake light goes on and off at the PRECISE moment that the tow vehicle brakes go on and off. On my Explorer, that wasn't the case. I found that when I take my foot off the brake pedal, the brake lights go out a fraction of a second before the truck brakes release. The result was that the trailer brakes released while the truck brakes were still on, and the trailer would SLAM forward into the hitch. It was very disconcerting, and would have beaten the hitch to death in a few thousand miles, I am sure. And there was no way to adjust for this.

That's more than my two cents worth, isn't it - I do tend to run on. But if you have the choice, my suggestion is that you go for a full proportional controller - and stay away from those time-cycle units!

Bill