How do I test a brake controller ?

[lizzyhermit]

the TT brakes engage but don't seem to be providing much resistance to forward movement with the controller set on full power. Can I hook up the ol' multi meter to the brake pin in the trucks connector and find a volunteer to hit the pedal as I watch? If so, what should I see on the gauge ?



And before anyone asks, I can't remember the controller manufacturer or model. I'm at work and the trucks not.

 

[RustyJC]

An inertial controller (other than one like the Prodigy, with a time-based ramping boost feature) won't provide any output if you hit the pedal while sitting still. A truly proportional controller like the Jordan or BrakeSmart should provide an output proportional to the braking effort. A time-based controller will provide the same ramped output (depending on gain and level settings) regardless of braking effort.



If you have a Jordan, the readout gives you actual current output (which is what you want to know) - each trailer brake should draw around 2. 5 to 3. 5 amps max, so a 4-brake trailer would draw 10 to 14 amps at maximum output. Other controllers may give a voltage output which really doesn't mean much unless you know the resistance (pure and inductive) of the brake circuit which would allow you to calculate output current using the formula I = E/R where I = current in amps, E = voltage in volts and R = resistance in ohms.



Another simple way to test the trailer brakes in a go/no go fashion is to take a compass and place it fairly close to each trailer brake. When the controller is energized, the needle should swing toward the brake in response to the magnetic field created by the electromagnet in the brake.



Rusty

 

[lizzyhermit]

thanks Rusty. The controller is a Draw Tite Activator that's been on the truck since new. The brakes do engage, I can hear and feel 'em somewhat but they don't seem to do much at full gain and level settings.

 

[HBarlow]

Your brake controller may be working normally but your trailer brakes could be misadjusted, worn, or defective. Have you tried adjusting them tighter? You could also have poor connections in the seven pin connector due to age, wear, corrosion, bent contacts, or poor connections at the brake wires. Normally trailer brakes have two wires exiting through the backing plate, about 12" pigtails, that are soldered or crimped to the trailer's brake wiring along the frame. The connections can be separated or corroded. You could also have weak brake magnets that are energizing but have insufficient pull. It is easy to determine if you have 12 volts present in the seven pin connector but more difficult to determine if you have limited current due to bad connections.



If your trailer brakes are old, the cheapest and easiest fix is usually a complete set of new brakes complete with backing plates magnets, shoes, hardware, etc. They can be purchased from RV dealers and trailer repair shops. The best source I've found is http://www.southwestwheel.com at about $90/pair. If you try to buy individual magnets or brake shoes you'll spend considerably more.



Harvey

 

[ndurbin]

It may not be the easiest but I've jacked one side of the trailer up and had somebody spin one of the wheels. Once it's spinning good ya hit the manual slide on the brake controler. At full power they should stop the wheels immediately.



Nathan