Trailer brakes

[Nytroxpress]

Hey all. Hope this cold weather is signs of things to come in the way of snow! -44 here with the windchill. Ain't fit for man or beast.

OK the reason I'm posting
I have noticed when hooked up to a empty trailer ( 5 or 6 different ones so far) bumper, or Fifth wheel when I apply my truck brakes ( digital trailer brake control set to 8)via the peddle on the floor my trailer brakes come on strong and slow / hold the truck back with no load on / in trailer. Now when I add a load turn my brakes controller up apply the brakes the truck ends up doing most if not all the breaking. I have noticed and currently figuring out the culprit that my left turn signal and break light fails to come on but should not be the cause as it works when trailer is empty. I have checked and rechecked the plugs on the truck (7 way) for proper wiring and all is good. I hooked to multiple trailers and eliminated them as suspects ( breaks work fine on other tow vehicles) any suggestions as to the problem

 

[zal]

With a load on, have you tried using just the brake controller to apply the brakes?

 

[papajake]

check your plug on the trailer for corrosion and clean then take a small aul and bend the contacts just a little to make good contact also you could have a bad ground wire going to the magnets on the brakes they just screw them to the frame and they rust

 

[Nytroxpress]

I agree with the suggestions and anything is possible. I could definitely see this as a possible suspect if it was only one trailer I hooked on to but that is not the case and as mentioned they work fine in other tow vehicles. That said I'll take ur advise and give it a shot. What can it hurt.

 

[Nytroxpress]

Yes I have tried to dynamite the brakes by manually triggering the brake controler and feels the same as if I depress the brake pedal.

 

[prelude48]

Sounds kinda like high resistance in the trailer brake wiring, loaded the brakes need more power to keep the magnet in the brakes active so it does its job, if there is a load on the trailer and brakes don't work that well i would look at wiring in trailer brakes on trailer and question brake shoe adjustment. Like the other guy said, check wires under trailer at each wheels for ground connection and crappy wire connections such as bad crimps that are not sealed and corrosion on the wires that may just pop apart when given a light pull. If i remember correctly bad connections cause less current to flow and causes heat due to resistance and results in low or no current flow and makes things not work or work half assed. Worked in a trial place for a few years and always found 90% of the issue in the trailer never the truck, plus if other trailers work ok with your truck then i would blame trailer.

 

[Nytroxpress]

I have hooked up to 5 or 6 completely different trailers. 3 fifth wheels 1 or 2 deck overs and a bumper pull enclosed. All having 7 way plugs. Empty the brakes on all the trailers worked as stated above. Loaded they did not also as stated above. I agree if it was just the one trailer then it would be the issue for sure. But when I unhook one of my trucks and re-work with a different one the breaks work as they should loaded and empty.

 

[Nytroxpress]

One trailer was brand new hauled home with another trailer lifted off at the shop and experienced same effect

 

[tex78]

What truck???

Factory control or aftermarket??

sent while drinking tea's

 

[Nytroxpress]

2007 GMC 2500hd duramax
Controler is a aftermarket
Tekonsha P3 (digital trailer brake control)
And it is set for electric brakes as all my trailers are electric brakes

 

[tex78]

Huh, we'll then either feed power to controller doesn't have enough Or controller itself doesn't output enough

Possibly the brake switch I suppose too


If u manual trigger does it do the same???

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[2010m8]

I know you said you checked the plugs on the 7 way on the truck but did you check for corrosion on contacts in the 7 way. Had I 2012 with the same problem and it ended up having badly corroded connections. Get some contact cleaner and sand paper and clean them.


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[tex78]

I know you said you checked the plugs on the 7 way on the truck but did you check for corrosion on contacts in the 7 way. Had I 2012 with the same problem and it ended up having badly corroded connections. Get some contact cleaner and sand paper and clean them.


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The 12 would have had the integrated control factory install

They are very sensitive to properly loaded to work right

Aftermarket ones don't much care

sent while drinking tea's

 

[2010m8]

The 12 would have had the integrated control factory install

They are very sensitive to properly loaded to work right

Aftermarket ones don't much care

sent while drinking tea's

Still a badly corroded connection would cause high resistance and for other things not to work a well. Could also explain the lights too.


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[tex78]

Still a badly corroded connection would cause high resistance and for other things not to work a well. Could also explain the lights too.


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I'm a bit confused now

Does the trailer lights go out all the time trailer is loaded and no matter what truck is hooked to it




My gut says bad ground on truck-trailer, and lights I bet just ground to the steel on trailer close to the lights, frame flexes and now bad ground

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[2010m8]

Sounds like it's 1 truck. With different trailers.


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[Merc63]

Perhaps your controller has **** the bed.

 

[TROLLCAT]

ground on truck wiring plug is faulty

remove and inspect wire harness going to trailer plug

 

[nathan#19]

A volt meter across the ground and brake pins in the truck plug while the controller is turned up and activated will tell you how many volts are going out. I would think it should get close to 12v......

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[tex78]

A volt meter across the ground and brake pins in the truck plug while the controller is turned up and activated will tell you how many volts are going out. I would think it should get close to 12v......

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Good idea, but no load on circuit


Do the same test with a sealed head light bulb between ground and brake power and see if it stays bright with Ir cranked up

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