Testing trailer brake controller....

BB_TX wrote:
Forget about measurements. Use a bottle jack to raise one wheel just enough to be able to spin that wheel. Have some one step on the brake pedal while you are spinning the wheel. If it locks, repeat with the other wheels. That will tell you if the brakes are actually working, not just if you are getting power out.

I currently have one tire completely off and bearings removed. I don't think they're working. Can I leave that apart and try this with the tire that is still on the rig, right next to it?

Forget about measurements. Use a bottle jack to raise one wheel just enough to be able to spin that wheel. Have some one step on the brake pedal while you are spinning the wheel. If it locks, repeat with the other wheels. That will tell you if the brakes are actually working, not just if you are getting power out.

That sounds good. Can you use the compass on an iPhone?

A quick and easy way to see if you are getting power to the brake magnets is to place or hold a compass near each brake while someone pushes the brake pedal on and off. If the compass swings the magnets are receiving power.

llr wrote:
in amp mode you are shorting the power to ground,

if you want to see the current draw the meter needs to be in amp mode and in series with the blue wire (cut the blue wire and one meter lead goes to both blue ends).

If you want to see the voltage output from the controller just change the meter to DC volts higher then 12.

I am not sure the issue or what you are trying to do so I can't advise on the better approach

Voltage output from the controller.....that tells me if the controller is sending the current out to the 7-pin and beyond, yes? If the lights are working does that mean it's sending out voltage?

I don't know what I want in terms of outputs and draws. That's lingo I don't know. I want to know if the controller is working. Then I want to know if the brakes are getting power, and if they work. I want to know things are working before I got back out on the road, without moving the rig.

You may need to check amps, but you're going about it wrong. What you're checking is the amps. draw to ground, or a dead short. Like llr said, you need to check the reading in series with the wire you're checking.

I am trying to determine if the brakes and controller are good without moving the trailer. I operate a business out of it and it's a mess and not easy to just pack up. I have to regrease the bearings this weekend and wanted to make sure the brakes are good before I close everything up.

I read an instructional page on testing and it said to test for amperes. gahh....maybe all this is due to some bad info.

in amp mode you are shorting the power to ground,

if you want to see the current draw the meter needs to be in amp mode and in series with the blue wire (cut the blue wire and one meter lead goes to both blue ends).

If you want to see the voltage output from the controller just change the meter to DC volts higher then 12.

I am not sure the issue or what you are trying to do so I can't advise on the better approach

You need to be looking for DC Voltage not DC Current.

The BRAKE CONTROLLER will produce a DC VOLTAGE output to each of the Brake Magnets.

If you are providing 12DCV output then each Brake Magnet will draw around 3AMPS of DC Current.

The Brake controller settings allow you to only provide enough DC Voltage so that the brakes do not drag but slow you down accordingly.

My settings is around 5-6 on the controller screen is somewhere around 6VDC being applied to the brake magnet when the brake pedal is pressed. When using the manual slider I can get around 12VDC going to the brake magnets on my OEM Ford setup...

If you have a mulitmeter set for MILLIAMPS and place the leads across the DC Voltage source it will blow your meter fuse. When using Milliamps setting the multimeter has to be in series with the DC load and the DC source to read the DC Current all of your brake magnets are drawing. For a dual axle this could be around 12AMPS DC Current... Most low cost multimeters do not have this high of DC AMPS reading capability.

Hopefully you haven't burned up your multimeter shunts now by placing your multimeter in parallel with the Dc Voltage source.

The way I test my trailer brakes everytime I hook up is hookup my 7-way connector after hooking up the trailer hitch and use my MANUAL LEVER ONLY on the Brake controller (Not the brake pedal) to stop my truck and trailer at the first stop sign I come to.

The newer truck electronics will not let you use your brake pedal for stopping the trailer electric brakes under 10MPH. At least that is how my FORD OEM Brake Controller is setup.

Hope this helps some...
Roy Ken