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Discussion Starter #1
Hi folks. I'm at my wits end on this one. The double axle horse trailer I have is simply not braking hard enough with its electric brakes. There is just barely enough grab when the trailer brake adjuster, which is brand new, is turned on to full braking. Even when using the emergency slide button on the adjuster, only a bit of grab is detected. I've tried the following to no avail.....1) adjusted the brake shoes further apart by turning the star wheel so that the wheels will turn only about one full rotation when spun by hand; 2) checked all the pertinent fuses under the dash and all are fine; 3) there is power for braking, running lights, and brake/signal lights at the wiring connector on the truck end; 4) there is power to all the trailer wheels and lights. I noticed that some of the brake wires on the trailer had broken beforehand, and I've spliced them back together the way they should be. I took one brake magnet to the store to compare with a new one, and it seems to be just as thick as the new one. So why am I not getting full grab such that the tires should lock up? Any ideas/info you could supply would be greatly appreciated. Thank you.
 

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Is this the factory ford brake controller or another one? How many splices in the wire? Are the connections good?
 

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Discussion Starter #3
The controller is not a factory install. The wiring harness however, is the original that came with the truck...4 wires: blue, red, green, white. The controller's wires are blue, black, red, white. I followed the installation instructions for the controller....controller's blue to Ford's blue, black to red, red to green, and white to white. A previous controller worked just fine, until it started to behave the same way as the new one is. I thought the old one had died, so I bought the new one, but no chance in performance. I discovered the broken wires on the trailer afterwards.

Maybe the problem is the wiring on the trailer. The way it is connected now, the brake wire (blue) goes from the truck to the back of the trailer. Then it splits, and sends one connection to the left rear brake, and another to the right rear brake. From the right brake, the ground wire returns to the left side of the trailer where it is spliced to the ground wire of the left brake and then riveted to ground on the trailer frame. For the front brakes, the main wire continues from the first split near the back of the trailer, where it splits again, sending one connection to the left front brake, and another to the right front brake. Each of the front brakes are individually grounded to the trailer's frame.

Could the problem be the magnets themselves? Do they lose their effectiveness over time even though they're not worn out? Hope this helps. Thanks.
 

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The magnets generally dont unless they are dirty. Sounds to me like a grounding issue on the trailer
 

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Discussion Starter #5
I drilled out the aluminum rivets that I used before to hold the ground wires to the frame of the trailer, cleaned the connections on the wires, and reinstalled the ground wires with screws instead of rivets. Still no change. I'm thinking of rewiring the whole brake wire, and/or replacing the magnets and brake shoes, an expensive venture if they are not the problem. Voltage at the connector on the truck reads a little over 12 volts when the brake controller is set to maximum with trailer unplugged, so there is power available to the trailer. Next thing to check is the voltage at each splice in the main wire leading to the magnets. If the voltage is the same, it may mean replacing the brake shoes next. I'll also try to locate where the main cable ground wire is connected to on the trailer to see if there is a clean connection. Right now I can't find it, but it must be working fine because the lights work. Any other thoughts or ideas? Thanks.

Jack
 

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Discussion Starter #6
Hey!!!! The problem was that I was testing the trailer on the local residential street at low speed and I expected the brakes to lock up when applied hard. At the suggestion of a local trailer sales person, I took the trailer out on the highway for a good number of miles, and lo and behold, the brakes worked when applied. I even had to back off on the brake controller so as not to lock up the tires. So it seems speed is the key....it would appear that the brakes need the wheels to be spinning quite fast in order to get the full stopping effect. What a relief....no need to replace shoes, magnets, etc. Whew!!!
 
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