Teach Me: Trailer Brakes!

I have been driving unsafe for years! I want to correct this problem! I haven't used trailer brakes EVER for all of the piles I have towed home. SOOOO.....

I have a trailer that has electric brakes. The trailer was made using axles from a mobile home. They seem pretty robust to me.

Anyway, the brakes are there, and so are the wires leading out of the wheel area. Then nothing. What do I need to hook them up to my truck?

I have a brake controller I got for christmas. It plugs directly into my truck (yea!).

The truck has the round type plug to connect the trailer wiring. The trailer has functioning brake / turn / taillights.

The question specifically is: What goes between the round plug on the truck and the brake mechanism? Do I hook the brakes to the brakelight wire? Do th ebrakes have a certain polarity? (can I hook them up backwards?).

I do not necessarily have to have the failsafe if the trailer breaks away if I don't need to.

Thanks,

Rob

E-Trailer

Lots of useful information here, and people you can ask.

Thanks!

I will check out that site.

That is the truck side of the wiring, not the trailer side.

Do you have a handy pic like that for the trailer side?

Thanks!

Rob

wvumtnbkr wrote: Thanks! I will check out that site. That is the truck side of the wiring, not the trailer side. Do you have a handy pic like that for the trailer side? Thanks! Rob

Do you have a round connector on the trailer now or a flat 4? It will need to have the round connector, find out which pin on that connector corresponds to the brake controller pin on the truck connector. Your brake wires should be connected to that pin.

Each brake will have two posts. The electric brake wire in the trailer wiring needs to be distributed to one of those posts for any brake you have. If it has four brakes, it needs to be split 4 ways. Usually the axle has a couple wires going across to the other side already.

The other post gets grounded. Its an electromagnet, so no polarity, I just like to stay consistent.

Look at the photo here. In this photo, the black wire would be split two ways and (in my case) hooked up to the front post on the brakes. Then both of the rear posts would get grounded.

did the brake controller come with instructions as to which wire does what? how about the website for the company that made it?

And, no... its not the brake light wire you use, its a trailer brake wire, usually blue, and should be #2 in the connector

Whoa, hold on a minute- You haven't given enough info.

Round plug- do you mean a 7 pin RV style plug (about 1 1/2" in dia), or a smaller 6 or 4 pin version?

Types of trailer plugs

You want the 7 pin.

Also- that previous diagram only shows the 2 wires required for the controller. There will be 7 wires. The rest are the ground, and the brake, parking, and turn signal lights.

If you buy the plug you need at Wal-Mart (or anywhere else), it will come with complete wiring diagram. Your new controller should have come with it as well.

What fail safe are you referring to? Breakaway units typically have mechanical disconnects, or onboard batteries to make them function once disconnected from the tow vehicle. There isn't any "connection" to the tow vehicle for a breakaway (unless it is a cable activated breakaway switch, which won't make anything work if there is no battery on the trailer).

BTW- Congratulations, and THANK YOU for stepping it up to a setup with brakes.

SVreX wrote: Round plug- do you mean a 7 pin RV style plug (about 1 1/2" in dia), or a smaller 6 or 4 pin version? BTW- Congratulations, and THANK YOU for stepping it up to a setup with brakes.

Agreed... Kudos on the brakes.

SVreX, I can't think of a single vehicle since about 1970 that has used a 6-pole round connector. He already identified in his original post that it was a round connector, and also identified that his truck was equipped with the wiring harness already present so that the brake controller just plugs in.

I realize I made some assumptions, but unless he had his newer truck custom-fit with a 40-year-old trailer harness, its a 7-pole.

As others have side trailer brakes work by magnetism. A oval electro magnet hang on a arm the top of the arm is a pivot the other end of the arm is fitted between the two shoes much like the wheel Cly would be on a hydraulic set up in the rear of the truck. Power the magnet (no poliarity needed) it trys to stick to the face of the drum making the arm move thus spreads the shoes. see pic in link http://www.etrailer.com/dept-pg-Trailer_Brakes-sf-Electric_Drum_Brakes.aspx

If a trailer is over 3500gvw Fedaral laws says it must have brakes and a mechanical break a way switch (wich means a battery too) I like this one have used it on 4 trailer so far. I like the fact it has a charge staus light, and its complete kit bater box status leds switch ect. http://www.etrailer.com/Trailer-Breakaway-Kit/Hopkins/20099.html One thing i do add to it is some thin rubber over the swich like old inner tube to keep water and mud other road crud off the switch.

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Thanks guys!

I was making it WAY TO COMPLICATED!!!!

I just have to ground one of each of the brake wires and run the other to the "blue" terminal on my round (7 pin) plug.

I checked the owners manual in the truck and it is the "blue" pin.

I just didn't know about how to wire the brakes on the trailer to the connector. In hindsight, I worded my initial post badly.

Thanks Guys!

Rob

No no no don't just ground one end run the grond back to the plug! or junction box this way you know the ground is there and the brakes will work.

curtis73 wrote: SVreX, I can't think of a single vehicle since about 1970 that has used a 6-pole round connector. He already identified in his original post that it was a round connector, and also identified that his truck was equipped with the wiring harness already present so that the brake controller just plugs in. I realize I made some assumptions, but unless he had his newer truck custom-fit with a 40-year-old trailer harness, its a 7-pole.

I have never used anything other than the 4 pin flats or the 7 pin rounds, but the 4 and/or 6 pin rounds have been on several of the used trucks I've bought over the last few years.

If he didn't have a brake controller, why would the truck have a 7 pin?

It didn't seem like such a dumb question to me.

Besides, who says his truck isn't a 1970 model?

SVreX wrote:

curtis73 wrote: SVreX, I can't think of a single vehicle since about 1970 that has used a 6-pole round connector. He already identified in his original post that it was a round connector, and also identified that his truck was equipped with the wiring harness already present so that the brake controller just plugs in. I realize I made some assumptions, but unless he had his newer truck custom-fit with a 40-year-old trailer harness, its a 7-pole.

I have never used anything other than the 4 pin flats or the 7 pin rounds, but the 4 and/or 6 pin rounds have been on several of the used trucks I've bought over the last few years. If he didn't have a brake controller, why would the truck have a 7 pin? It didn't seem like such a dumb question to me. Besides, who says his truck isn't a 1970 model?

Or his whole connector could be aftermarket, they still sell the 5 and 6 pin connectors.

While we're on the subject...is there anything special I need to know about adjusting the brakes? My trailer doesn't seem to stop with much authority even at the maximum controller setting. I mean, it creates drag, but I've never really had them lockup. The thing is used, old and I don't know if they've ever been adjusted aside from me fiddling with them (and I find the experience of trying to adjust them tremendously annoying).

ddavidv, sounds like its time to pull the drums and check the shoes

In reply to ddavidv:

Yea, most axle manufactuers sell rebuild parts for thier brakes. I got a complete set of mine after all of the wires broke internally. Now they work like a charm.

I would bet all you need to do is swap the magnetic pucks.

ddavidv wrote: While we're on the subject...iI've never really had them lockup. The thing is used, old and I don't know if they've ever been adjusted aside from me fiddling with them (and I find the experience of trying to adjust them tremendously annoying).

95% of the trailer brakes out there do not self adjust however DEXTER did come out with self adjust ones The design of Nev-R-Adjust™ brakes utilizes an innovative forward self-adjusting feature. It uses the brakes the shoe pulls on a cable conected to a rocker and hits the star wheel.

Some drums will have a 1/2 wide slot cut in the face so you can see the shoe wear and also use for adjusting with a .020 feeler gauge.

Other things that weaken trailer brakes. 1) Is the magnet will rust to the arm and be held off the drum face. Pull the hub and drum and see if the magnet floats on the arm theres a spring in there to push it out but they still rust up offten. Antiseze works for a while but just a dag you don't want it to ozze on the the magnet face. 2) Grooved up drum face for a worn thin magnet. Most shop don't surface that face but trailers need it to grab the magnet. 3) Worn Magnets. Take a good look at the magnet the ends of the oval should have a 45 deg bevel on them. if not there worn also near the center you should see tinny pin holes in the iron. Just like race slicks the holes are wear indicators no holes no iron left thus less grab power and not long before you find copper windings.

Get on E-Trailer, trailer parts superstore (eastern marine) , Adventure RV.net and look for whole units! Shoes will run you $35 per wheel. Offten in the winter you'll find 100% new whole units for $25! Fact i just put a set on my WellsCargo that are self adjusting units from Dexter i bought 3 years ago when they had just come out for $25 per wheel! normaly close to $100 per wheel. You can't rebuild'em cheaper then a replacement.

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SVreX wrote: If he didn't have a brake controller, why would the truck have a 7 pin? It didn't seem like such a dumb question to me. Besides, who says his truck isn't a 1970 model?

Auto manufacturers didn't start putting direct-fit wiring harnesses in trucks until 88. Its not a dumb question, like I said I was assuming things.

The reason I assumed it was because when you get a factory "tow package" it comes with that plug under the dash and a 7-pole connector. When he said it had the direct-fit connector under the dash, that told me it was 88 or later and had a factory-installed 7-pole connector... so unless the 7-pole had been removed and replaced with an older-type connector... yadda yadda.

I should have been a detective

Sorry for the confusion!

The truck is a 2008 Nissan Frontier with the factory tow package (and 7 pin round connector).

I will hook the ground wire up to the ground on the connector.

Thanks again everybody!