electric brake magnets

[Hooked_on_HP]

I am working on a friends 3 axle enclosed trailer. The electric brakes on the left side work perfect. The brakes on the right side wont work unless you apply over 11 volts. I took the hubs off the right side and checked the voltage at the magnets. I have the same voltage as I have coming out of the truck. When I have under 11 volts going to the magnets they wont work. If you put a screwdriver on the magnet it wont hold it, If I increase the voltage over 11 volts the magnets work. Shouldn't the magnet get stronger as the voltage is increased. I thought it should be magnitized at as low as 2-3 volts.I thing I have a ground issue but cannot find it. On this trailer all the wiring runs along the left side of the trailer and 2 wires run through each axle tube to each brake on the right side. On my trailers I have one wire going to the magnet and the other wire coming off the magnet goes to ground. I am assuming the second wire goes back to the harness and shares a common ground. Is there any reason I shouldn't ground each brake individually. BTW it has torsion axles.
Bill

 

[Travelover]

By far the biggest source of trailer electrical problems are poor grounds. My recommendation is to run a separate ground wire from the front harness plug connecting to each brake and light and not rely on the frame at all. You can ground each brake separately, but again, relying on the frame sets you up for corrosion problems later.

 

[Diamondpilot]

No reason you can not do new individual grounds.

You have a ground issue or a current issue. You can have voltage but very little amperage. Is the wiring in good shape and properly sized? For 6 braked system with a 25' run from the plug to the first brake it should be no less than 10 ga for both positive and grounds.

Chris

 

[Hooked_on_HP]

Chris, this trailer is 7 yrs old but probably doesn't have 5k miles on it. The brakes did work perfectly. This is a problem that just started. I am assuming that the factory wiring is sized properly. I think you are on the right track with the amperage. I will have to take a closer look at where they connected the wires to go from one side to the other. I wish I could get the trailert up in the air about a foot. It would make it easier to crawl around under it.
Bill

 

[Diamondpilot]

Chris, this trailer is 7 yrs old but probably doesn't have 5k miles on it. The brakes did work perfectly. This is a problem that just started. I am assuming that the factory wiring is sized properly. I think you are on the right track with the amperage. I will have to take a closer look at where they connected the wires to go from one side to the other. I wish I could get the trailert up in the air about a foot. It would make it easier to crawl around under it. Bill

My guess is if the grounds are good there is corrosion somewhere in the positive wiring causing the issues.

Chris

 

[Travelover]

......... I wish I could get the trailer up in the air about a foot. It would make it easier to crawl around under it.
Bill

Can you stack some boards to make a temporary ramp?

 

[Soundguy]

yep. jack and crib and jack and crib...

 

[The Fred]

If you can't find a ground issue ohm the magnets and see if they all are close. I see lots of those cheap scotch-lok connectors that should be banned from outside use.

Also you could voltage drop the ground side of the magnets just need someone to hold the brake controller on for you.

Good luck, Fred

 

[Soundguy]

. I see lots of those cheap scotch-lok connectors that should be banned from outside use.

AMEN brother.. preach on!

 

[newbury]

Chris, this trailer is 7 yrs old but probably doesn't have 5k miles on it. The brakes did work perfectly. This is a problem that just started. I am assuming that the factory wiring is sized properly. I think you are on the right track with the amperage. I will have to take a closer look at where they connected the wires to go from one side to the other. I wish I could get the trailert up in the air about a foot. It would make it easier to crawl around under it.
Bill

Age and mileage mean diddly squat.
My 2007 Hudson had been parked in my driveway for 4 years. Last year I had 3 times where a light would stop working. Each time I drilled a better contact point to the frame.
Oxidation knows no bounds.