Freakin trailer brakes

Hooked up a new Teknosha P3 brake controller, and thought all was well. Hooked it up to a loaded trailer today with electric brakes, and I get a "NO
TRAILER CONNECTED" message on the display. Manual controller does not send any juice back to make brakes function. Had set the controller to 6.0 as per directions. Seems electricity is not reaching wheels, or even past coupler, which is just long enough if I don't make any turns. Have to lengthen that a foot anyway.
Guess there is a loose frammel somewhere. 90% of the time, in my experience, it is a loose or broken ground.
Do I just take a 12 V. battery back there, take the necessary parts off, and hit it with some juice to see if the brakes are even hooked up? I just got this trailer, and have not had the hubs off it, and don't even know if it has brake shoes on it. If I do hit the wire with some juice, the brake should just function, right?
I am reluctant to do much with the controller, as it says it is easy to short it out, and it will fry it instantly, no refunds.
Guess the right way is to just jack it up, take the wheels off, take the hubs off, and see what's there.
Do I adjust brakes like others, with a spoon or long screwdriver until they just make contact, then back them off until they quit rubbing?
Right?
Shortcuts and diagnosing expertise welcomed.
Steve
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wrote:

Have you put an ohm meter on the trailer wiring yet? Find the pair that comes off each wheel and check it for continuity, then hook em together (in parallel and hook it to your controller. Zip cord, telephone wire..just about anything will work for the test.
And make sure the wires from the brakes come back to the proper pins on the connector, after you have determined that the brakes are indeed working.
Oh..and put a 5 amp fuse in line with the hot wire for the controller output. Or maybe a 8 amp? Anyone? Ive no idea of what amps trailer brakes operate at. Ive got a 10 amp on mine..but its what I had on hand once..shrug 2 brakes.
This might help....
http://www.etrailer.com/question-15680.html
Gunner
One bleeding-heart type asked me in a recent interview if I did not agree that "violence begets violence." I told him that it is my earnest endeavor to see that it does. I would like very much to ensure - and in some cases I have - that any man who offers violence to his fellow citizen begets a whole lot more in return than he can enjoy.
- Jeff Cooper
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Steve B wrote:

Broken ground or bad wiring.

Yes to a point. You should hear it when they apply, but if they are rusted or broken you might not.

Yup, Also will tell you if the hubs are OK and show other problems.

Maybe. All depends on who made the brakes and which type they are. Some adjust that way, others self adjust with a slider and some just wear out.

--
Steve W.

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On 8/13/2012 11:23 PM, Steve B wrote:

If it's more than a single axle, remember, they are to be wired in parallel, not series.
A battery and controller sitting by the wheel might help.
Wire it up and squeeze the tit. See it the brake moves.
Check them all, If they all work, back track through the wiring to the connector.
DON'T use the trailer frame for ground!
And a circuit tester with a light works better than volt meter.
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wrote:

Commercial trailers have been using the frame for ground for decades - and it works if it is done PROPERLY. Harder to screw up a fround WIRE than a frame, but also easier to damage the WIRE. Six of one, half dozen of the other, in my books. I'll stick with a "chassis ground" - same as used on the tow vehicle, and same as has been used for decades.
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On 8/15/2012 6:38 PM, snipped-for-privacy@snyder.on.ca wrote:

A screw connection (from connector to frame) and another (from frame to brake)?
I'd prefer a wire to wire connection - ANY day.
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On Wed, 15 Aug 2012 19:38:19 -0400, snipped-for-privacy@snyder.on.ca wrote:

Don't most automobiles uses a "frame ground" :-) Cheers, John B.
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John B. formulated on Thursday :

No.
--
John G



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wrote:

Most don't? Funny, I've worked on vehicles ranging from a 1937 Chevrolet through British and Japanese autos as well as trucks up to 50 tons and a mess of heavy equipment - bull dozers, earth movers, cranes, etc. And I'll be damned if I can remember one that didn't use the frame, or in the case of these new fangled things without a frame, body, ground.
Cheers, John B.
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On 8/16/2012 6:48 AM, John B. wrote:

They didn't use microprocessors to control electrical things in 1937...
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wrote:

No they didn't but on the other hand I just went out and looked at my wife's Honda Fit and the negative battery cable runs directly from the battery terminal to the car body and there is a separate cable to connects the engine to the car body. The car, I might add has a computer controlled transmission and engine. Cheers, John B.
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On 8/16/2012 7:24 PM, John B. wrote:

well, there you go. now ya know.
But for trailers, I'm still running wire to wire whenever possible.
It's(all) just that all (those) extra connection(s) from wire TO frame, FROM frame to wire.
What are you recommending that we recommend, John? At the other end?
Drill a hole in something and screw it? Well, ok. But i prefer to run wires. And I solder sometimes too, dam it.
a tip for the gang?
Twist tops verses Press-In Clips.
Those press in clips s u c k. Things just corrode away slowly and quickly, at the same time. Dissimilar metal ain't the least of it. You might get it working ok. But that's where those things most often fail. Wrap it and cap it.
If you are really serious solder it.
for the connection is blessed.
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wrote:

"signal" grounds are wired. "power" grounds still use the chassis on MOST vehicles today. Even most with CAN-BUSS controlled devices.
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Try a 60's Morgan.....
--
A host is a host from coast to snipped-for-privacy@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
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wrote:

My 2001 Ranger is frame grounded for most items. Shrug
Gunner
One bleeding-heart type asked me in a recent interview if I did not agree that "violence begets violence." I told him that it is my earnest endeavor to see that it does. I would like very much to ensure - and in some cases I have - that any man who offers violence to his fellow citizen begets a whole lot more in return than he can enjoy.
- Jeff Cooper
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wrote:

Correct. And I recreated all sorts of wiring looms for autos for which no harness was available back when I worked at the body shop.
Only the Brits, using "Lucas, Prince of Darkness" technology, use body and frame grounds. Ask any Brit car owner how he likes it. But be prepared to run. Some are _really_ fired up about it.
-- All of us want to do well. But if we do not do good, too, then doing well will never be enough. -- Anna Quindlen
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On Thu, 16 Aug 2012 07:03:50 -0700, Larry Jaques

I beg to differ with you. Body grounds were very common on every American,Japanese, or German car I ever worked on as a professional mechanic , and my current vehicles (OK, they are 10 years old) still use chassis/body grounds for the majority of the circuits. Tearing the wiring harness out of a friend's Miata, there were numerous "ground points" where the black ground wires were screwed to the body/chassis and a friend's F150 also used body grounds extensively - and one that was connected to a patch of ferric oxide caused considerable problems untill it was located (and the windsheild fixed to prevent more rusting)
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On Thu, 16 Aug 2012 23:34:38 -0400, snipped-for-privacy@snyder.on.ca wrote:

Perhaps this came about since '85, when I retired from wrenching? I don't recall seeing too many frame grounds and NO body grounds except for a few on the firewalls, which mostly connected harness grounds together.
But the Brits grounded each lamp/motor at the site, creating a nightmare for the owners because the fenders/bonnets/doors developed rust between parts and the oxidized contacts didn't permit proper electrical flow. Watching a Brit car on a back road at night, you'd think they were a Morse code billboard. <blink, blink, b, b, blink>
-- All of us want to do well. But if we do not do good, too, then doing well will never be enough. -- Anna Quindlen
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On Thu, 16 Aug 2012 21:10:06 -0700, Larry Jaques

I've been wrenching since 1968, and on just about any make you can name - and ALL of them used a chassis return ground for MOST of the circuits. Yes, on many makes there were a cluster of wires brought out to one ground point where they screwed to the body - but even many American vehicles grounded the tail lights - for instance, by bolting them to the body, and the bulb socket grounded to the pot-metal lamp housing. OK until it turned to dust. Or to the cadmium plated steel lamp housing. Which sometimes rusted out. Or the socket rusted out.
But just about as many power wires corroded off at the socket, or inside the harness - particularly where wires were joined together in the harness, way back in the taped-up mess of wires. A whole lot EASIER to find and repair a bad chassis ground than a bad wiring harness - and you can take THAT to the bank!!!!
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On Fri, 17 Aug 2012 22:28:34 -0400, snipped-for-privacy@snyder.on.ca wrote:

Like the '83 "K" cars with the door lock/power window harness crossing under the dirver's floor mat and all the connections spot welded and protected with a fold over of cloth friction tape - maybe OK in a dessert environment but less than ideal in the snow/salt belt.
--
Gerry :-)}
London,Canada
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