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Sat Feb 23, 2008 6:20 pm

I am trying to wire a trailer for electric brakes. The question I have, has anyone ever wired electric brakes for a trailer? Do you wire them in series, or do you wire them parallel?
What is happeing for me, I am getting power, but not getting any brake action. I have them wired parallel. When I hook a test light the circuit, the brake controller in the tow vehicle reads brake action, but without the test light plugged in, it acts as if no trailer is hooked to the contrller.

Sat Feb 23, 2008 6:38 pm

Parallel.Check your grounds.

Sat Feb 23, 2008 6:40 pm

The Noof wrote: Check your grounds.

Thats what I thought , the test light is the ground when hooked up.

Sat Feb 23, 2008 6:42 pm

You run them parallel. I don't know why you couldn't wire them in series though. Once you apply the pedal they both need juice at the same time. They are simply a solenoid that engages the brakes when you juice em up. The controller gauges how much juice they get (more or less stopping power). It sounds like something simple like a bad ground or something.

Sat Feb 23, 2008 6:43 pm

Isolate the problem to the trailer side or the vehicle side. Apply 12 volts across the appropriate leads in the connector, you should hear the brakes click.

Sat Feb 23, 2008 6:48 pm

My electric brakes are wired into an inertia sensor, that varies the voltage in relation to how fast the tow vehicle is stopping.

If you wire them just into your brake lights, you will lock the wheels on the trailer everytime you press on the brake pedal.

You need an actual electric brake controller for electric brakes.

Sun Feb 24, 2008 5:41 am

Wire them in parallel. If you wire them in series and the first one in the series fails electrically there goes the second one too.

Sun Feb 24, 2008 8:17 am

Russ Wolfe wrote:
You need an actual electric brake controller for electric brakes.
X100.

Sun Feb 24, 2008 8:21 am

Foxx wrote: Russ Wolfe wrote:
You need an actual electric brake controller for electric brakes.
X100.

Read his post..."the brake controller in the tow vehicle".

Sun Feb 24, 2008 11:08 am

could be a bad unit too,.
either way, you'd be surprised how often people try to get around having to get one.
i did miss that he said he had one.

Sun Feb 24, 2008 11:26 am

So did I.
My wife ihas the tow vehicle at church, or I would go out and get the wiring diagrams. I keep them in the storage under the passengers seat.

Sun Feb 24, 2008 11:45 am

Thanks for the info and help, everyone.

I am ashamed to admit, it was a bad ground :oops: Not sure how I missed that one?

Sun Feb 24, 2008 11:57 am

You should always have a good ground between the trailer and the tow vehicle. Don't depend on the hitch for the ground.

Mon Feb 25, 2008 4:40 pm

bugntjw wrote: Thanks for the info and help, everyone.

I am ashamed to admit, it was a bad ground :oops: Not sure how I missed that one?

Yeah those will bite you.
Had a friend towing a trailer to the race track in the daylight with no problem.
Going home at night his tail light circuit activated his trailer brakes.
He ended up smoking a tire down to the rim.
Bad ground was the culprit.
.

Mon Feb 25, 2008 10:18 pm

This is a freshly built 19'8" flat-bed trailer, tandem axle, built to haul the sand toys (Flat-Fender Willys Jeep) to Pismo Beach. My uncle did the engineering/building (with me as a gofer) and I was in charge of painting and wiring. I did my research (as best I could) for wiring. I knew all of the connections were correct at the pigtail. I was running the lights and the brakes on total seperate circuits (even with the break-away brakes with battery pack). I just managed to have a bad ground for the trailer brakes. I thought I had checked the ground, but I guess I either hadn't, or not thoroughly enough.
Anyways, thanks for all of the ideas, everyone, and the help.