I found out a while ago that my trailer brakes were wired into the trailer lights, NOT into the connector at the front of the trailer. I asked the shop guy if that was a problem and he said not really, they still work but it's just not done PROPERLY. He said it's actually pretty common... especially on older and/or low-budget trailers... I didn't have to fix it if money was tight (and it was).

But I've been having trouble getting the trailer brakes to not lock up when I step on the brake pedal even a little bit... so this morning I took the trailer back to the shop.  He drove it and re-adjusted the pendulum/leveling dial.  Once he did, he said the brakes felt normal to him.

My friend sent me this comment:

"You would never get me to tow a trailer that has been wired this way. You can have the greatest and best controller out there, and this is not going to work. The electric brakes "must" be on their own circuit, and the brake lights themselves on another circuit. Trying to run them both thru the same wiring is asking for trouble. The rewire is in order, if this is truly what you have. It would almost seem to me that being wired the other way would actually be a violation of DOT rules.

Brake controllers usually have a power setting so you can match it number of axles with brakes(not all dual axle trailers have brakes on both, something else you need to know) and then the weight of the trailer. Electric brakes use magnets in the wheels to apply the brake shoes. The power setting determines how strong the magnetic field is for that purpose. The other setting is for setting the "pendulum", which senses just how hard you are trying to stop. In normal travel, it will hang fairly straight up and down. When you start to stop, the pendulum swings to tell the controller just how much force is being put into the stop. This is how the controller knows how much juice/power to send to the brake magnets.

When the brake lights and the brakes themselves are tied together, you are using part of the power to activate the brakes to the lights themselves. So you have just introduced a by-pass into the circuit, so that the power to activate the magnetic field may never fully develop.

The other thing that is very important with the electric brakes, is the ground. If you have a rusty or faulty ground, you are also limiting the effectiveness of your brakes. Rust will act as a resister, lowering the power transfer thru that circuit. So if the trailer has some age, a little rust, wired as described above, you have a very large chance of finding yourself without brakes when you really need them.

I highly recommend that you spend the money and get the wiring fixed so it is done properly. I consider what you have now as being quite dangerous."

Who is right, the shop guy or my friend?  Do I need to get the wiring fixed to be safe? 

Your friend is very correct!

AAAAAAAAAAAAERRRRRRRRRGH! 

Just got off the phone with a different trailer shop.  This guy listened to my story, promised to check it out for free, explained electric brake wiring to me, asked a lot of questions, and then told me I didn't need to come in because if the green light on my brake controller comes on when I plug in the electric, which it DOES, it means the brakes are wired directly to the correct place on the wiring harness and talking properly to the truck (ie brake controller).

I don't know what the guy at the first shop has been smoking, but apparently they would have happily rewired my trailer without cause.  (They even wanted $200-300 for a job that I've heard is pretty quick and easy.)  Hell, I just found out they charged me like $40 just to look at it and give me an estimate!  (Though they probably wouldn't have charged me if I'd had them do the work... I hope...)

After I pick up my trailer tonight I will never be frequenting that first shop again. 

Unless, of course, y'all tell me the SECOND guy is on crack and his statement about the green light is wrong. 

I'm telling you the brake controller will only "see" an electrical load.  That load, if as you told us in the original post is wired to the brake lights.  The controller doesn't know that, it sees a resistance and thinks everything is Okay.... hence the "green' light.

You said the brakes are not working correctly...  I trust your observations.  I don't trust someone's twice removed diagnois of a problem...  Neither should you.

As always, I have to begin by saying that trouble shooting a trailer, especially wiring, is always difficult via the internet.

Having given the usual disclaimer, I am pretty sure that if your brake lights were truly operating your brakes, then you would also apply the brakes to one side when you turn on your signal light.

You could do some pretty easy tests to determine how your brake controller is hooked up, but my suspicion is that it is likely hooked up to your brakes rather than your brake lights doing the work.

I would recommend that you:

• Jack the trailer up.
• Get a standard battery charger and ground it to the trailer.
• With a nail hooked to the hot lead, turn the charger on a low setting.
• Then systematically touch the nail into the plug.
• Do not put it into the big hole as it is the ground. If you do, the charger will spark a little, but shouldn’t cause any damage if you pull it immediately
• As you go through the other holes you should find
• 1 hole of the plug may (or may not) work the dome lights
• 1 hole works the clearance lights (may also work the domes)
• 1 hole works the right turn light
• When you find this one, see if your wheels turn. If so, you are not running the brakes off of your tail lights
• 1 hole works your left turn light
•  When you find this one, see if your wheels turn. If so, you are not running the brakes off of your tail lights
• 1 hole should work your brakes

If all the above checks out – tadaa, you are set and shop number one was mistaken.

Hope this helps.