Is there a way of testing electric brakes on a trailer without hooking up the tow vechile and just using a 12v battery to see if they work? I pulled the drum off and looked at the brakes and it's confuseing how they work. It's a trailer I just built with new axles and 1 axle with brakes and not on the road yet. Thanks, Tom

 

The link below is for Champion Trailer Company and is a long discussion of trailer brakes of various types including electric. Scroll down--a long way---to the section "Troubleshooting Trailer Brakes From the Trailer Side". You'll find the answer to your question there. This site has a lot of good information on trailers. It is primarily for boat trailers because that is what they manufacture but almost all of the information can be helpful with any trailer.

http://www.championtrailers.com/brkart.html

Hope this is some help.

 

Maybe I missed it on the link, but you can ohm out all the lines to see if you are losing any thing through a bad connection or wire..."resistance is futile",sorry,bad joke.But an ohm meter will show if all the power you start with is gettin where you want it. And, by the way,that IS a great link.

 

Why is it a bad idea to have the electric trailer brakes grounded on the trailer frame?

My system is grounded on the trailer frame as well as grounded on the truck side. Is this a problem? I thought it would just be extra safety having 2 grounds.

 

Moved to proper forum.

 

The main reason not to use the trailer frame as the only ground for the electric system is that the only connection to the tow vehicle to ground the circuit is through the ball. If you have grease or dirt or anything else on the ball or in the socket you may not get a good ground and have no electric brakes when you need them; also your stop, turn and running lights may not operate properly. I don't know of any reason not to use both a wired ground and the frame. It's sort of like wearing suspenders and a belt. However, I have read that using the trailer frame as ground increases the galvanic action between different metals on the trailer speeding up corrosion at the point of contact. I've never seen any practical proof of that; it may be more theoretical than actual.

 

You need a really reliable ground for electric brakes because of how they work. The brake controller varies resistance on the brake circuit to control the voltage sent to those solenoids that actuate the brakes. The controller is counting on a good clean, ground, because if you have a bad ground there will already be a lot of resistance in that circuit. If you use the ball for ground, then the resistance on that ground will vary as the trailer moves, and that'll make the braking force vary with it.

Most trailers I have seen use the frame as a ground the same way a car or truck does. As to galvanic action, that is usually handled by putting a grounding strap between the dissimilar metals. My horse trailer and car hauler both have those. In any event, with the frame on truck and trailer both being used as ground, you're going to have a potential ground through the hitch gear no matter what you do. The problem with that source has already been mentioned- it's a crappy ground because resistance across the hitch gear can go all over the place and cause the brakes and lights to function erratically. The lights are on thing, but the brakes need a given voltage to apply a given amount of force, if the resistance is all over the place, so are the volts passing through those solenoids. It makes for a messy tow.

The auxiliary ground is there to make sure that the current gets back to the truck's electrical system in a reliable manner. It's really no sewat for the manufacturers most the time, because it'll just be a short run from the plug to the respective frame. That's all they usually are.

 

It's early, maybe I'm missing something. Does that mean I'm ok with grounding both the truck and trailer, or should I remove the ground on the trailer?

 

Seetwisted, how would I ohm out the wires? I have a digital volt meter.Tom
Tekrsq, you only have one ground , going from wire to wire is more reliable then going from wire to frame then back to wire, and you hijacked my post but that's OK with me. Tom

 

Tekrsq:
It is OK to keep both the trailer frame ground and the ground wire to the trailer plug. In fact it is probably preferable. A lot of trailer lights are grounded to the trailer frame. Check the lights on your trailer and see if they only have one wire going into the socket. If so, these lights depend on the frame being grounded through the hitch ball which may have the problems mentioned in earlier posts. If you leave the ground to the frame it will tie both grounds together and your lights will be more reliable.

TomRooster1:
Is your test meter just a voltmeter or is it a VOM or multimeter? If it is purely a voltmeter you can't measure Ohms with it. If it is a VOM or multimeter it probably will measure Ohms. Different meters have different ways of doing this but your owners manual for the meter should describe the process.

 

Ground is passed through a standard 4 or 7-pin trailer connecter not the ball.
Although there is some degree of ground connection though the ball it is very unreliable.

The ground wire on the trailer side of the connector is attached to the trailer frame. The ground wire on the tow vehicle side of the connector is ultimately attached to the vehicle frame and neg battery.

 

Tom -

Because you're gonna need a breakaway system for that trailer before you hit the road, why not install it now and use it to test the brakes?

Steve

 

Keep the direct ground connected. You need that to make sure the electrical stuff works reliably on the trailer.

 

Good idea with the breakaway switch!

Then all you have to do is jack it up, remove the plug from the truck, and yank the breakaway pin. From there, it's just a matter of going around and making sure all the wheels with brakes won't spin for you. That's how I always checked them, actually.

Your only caveat there is to make sure your breakaway battery is charged and wired in according to the stuff they should've given you.

FYI, a number of brake controllers now have diagnostics built into them. The Tekonsha Prodigy, for example, will tell you when you have a fault in one of the solenoids. I'm pretty sure the TowCommand has that built into it as well. The only problem there is that neither one will tell you which one is bad.

If you really need to troubleshoot electric brakes, Dexter Axle has a primer on it at their website here:
http://i.b5z.net/i/u/1080235/f/6-8K%...-05_80_res.pdf

 

Sorry Tom. I didn't mean to hijack the thread. I just figured since they were making a big deal about the grounds, this was the time/place to ask.

I just put a new axle & breaks on mine and have yet to put a break away on either. Thought this was a good time to learn something, lol.