Brake Controller

This is first trip I have made with a new Prodegy Brake Controller. Everything seemed to be normal until yesterday. For some reason the reading would range between what I think is normal (0.0) and .3, .4 all the way to 1.4 with no application of the brakes. When we stopped for the night I could hear a humming from the area of the wheels (the controller was reading 1.4 at the time) which stopped when I disconnected the power from the tow vehicle.
I think I will have to cut the power to the controller today (Sunday) because I don't want to burn out the brakes and we will be driving only about 150 more miles to Las Vegas where we will be for a few days and I can get service.
In what I think is an unrelated problem, the electric tongue jack failed. I replaced the inline fuse (connected directly to the battery) which got the light to work but when I tried to operate the jack it burned out again. Hand operating it is no big deal but that is not what I have it for. Any ideas?

Iver,

These electrical gremlins are really hard to diagnose from a distance. I could be successful at solving the problem if I was there and had my Fluke meter in hand.

That said, go back to basics....Did this TV and trailer work together with a different brake controller? If so, then I suspect the wiring to the new Prodegy has been mixed up.

But if this TV and trailer and controller are new to each other, then the diagnosis follows a different route. I would start at the TV female trailer connector and using a smaller 12V headlight bulb as the electrical load, check each of the 7 pins for correct function. The one center pin may not be used, but the other 6 perimeter pins have specific and necessary functions. The specific functions may be embossed on the snap cover of the connector. The 3 to 5 amp load of the light bulb should be handled just fine by the brake controller when you hook it up to that pin (I don't have the pin diagram in front of me now). If all functions are good, then go on to the trailer side of the connector.

I usually use a 5 to 10 amp battery charger as the 12V source for checking the trailer wiring. But use a meter or small test light first to see if there is any voltage available at the trailer side pins. There should be only one pin showing 12V, it is the trailer batt charge line. If any others show a voltage, it means there is a short circuit somewhere in the trailer 12 V system. With nails attached to the battery charger clamps (and taped to prevent shorting), you can insert the voltage into each pin one at a time to determine if that function is working correctly.

Before doing the detailed diagnostics, I'd check to see that the coach battery is correctly installed. The negative side of the battery should be hooked to the trailer frame (ground). If possible, use a meter to determine that the battery polarity is correct (it is possible to charge a dead battery backwards and get reversed polarity). Next, check the stop and turn signal bulbs. I have seen where a burned out bulb shorts out to the tail lamp (running lights) circuit. Shake the bulb to see if either filament is broken. If in doubt, replace the bulbs, they are darn cheap. Because of the intermittant nature of your problem, I really suspect the #1157 tail/turn signal bulb is the culprit. Of course there could be a chafed brake line wire along the trailer frame, or going through the axles, but usually that means a lot more amps than the 1.4 you are indicating.

Good luck, and tell us what you find.

Paul_in_MN

Thanks for your imput.
Had it checked out today. It was wired wrong so that the brake pedal application did nothing with the trailer. The slide application was wired correctly. I am not happy wiith the maintenance people that put it in. Drove over 700 miles and some 7% grades like that ...I am not happy.

Whoa.....

This confirms once again why I like to do my own work. Sure I am slower than any commercial shop would be, but I double and triple check what I have done. There is just no excuse why a vehicle went out the door without the brake function being checked. I'm glad you made your destination safely!! I had a somewhat similar experience about 15 years ago when a fairly new controller (NOT tekonsha) failed in heavy traffic locking the trailer brakes hard. I was blocking rush hour traffic on a main road during Friday afternoon rush hour in Duluth MN (a city of very steep hills). My only choice was to cut the hot feed wire to the controller so that I could get out of the way. Boy did I drive slow on those hills after the rush hour traffic had subsided...knowing that I had no trailer brakes. I found an RV shop still open NW of the city and they confirmed the brand of premium controller I had bought had a high failure rate. I have only used Tekonsha since, and never had a failure.

My advice on checking the brake and turn double filament tail light bulbs is a unexpected failure that most people do not find related to the brake controller. But here is how it can work. The heavy duty filament (brake and turn) usually breaks first and wiggles around inside the bulb. If it touches the lit tail light filament, then the tail light circuit can back feed the brake circuit, sending voltage back to the controller. But it is smaller current than normal brake action and is often intermittant as the broken filament wiggles back and forth from the motion of the trailer. Depending on the internal circuitry of the controller, it can cause the trailer brakes to jerk with no foot on the brake pedal. I suspect the Prodigy is designed to prevent this problem. But I spent a bunch of time searching for the problem with a previous trailer and TV. So when I have electrical problems, I start with a check of all the lights, and then for corroded ground connections (which is a major source of intermittant light and brake problems).

Glad you got fixed up and can continue your trip with the peace of mind that everything works correctly.

Paul_in_MN

I want to give a shout out to Al at Johnny Walker RV in Las Vegas for taking me in immediately. His people had it fixied in less than half an hour. If you need anything worked on in Las Vegas this is the guy to see.