testing electric brakes without t.v.

Another thought on taping into each wheel magnet brake wire with an external 12VDc source.. These are pretty important on being sure they are making a good connection. I don't know if I would want to disturb any of these connection just to make a test. I might not get them tightned back up like they should be.

Use a compass - listen for a tone- or use a clamp-on DC ampmeter (SEARS or AMAZON) to read 3AMPS on each brake wire... Or spin the wheel and see if it engages when turned. ALso my brakes make a somewhat loud mechanical noise when being engaged..

Roy Ken

Some folks will use a compass and when 12VDC is applied by pulling the emergency break-away switch the compass will move big time telling you the brake magnet has been powered up.

You can also measure the current if you have clamp-on DC ampmeter. Each brake magnet will pull 3AMPS with 12VDC applied.

If you are real energetic you can jack up each wheel and when you apply brake power you should be able to lock-up each wheel after it does a 1/4 turn or so...

Also all of my brakes emits a tone when power is applied. I have to get real close the brake magnet to hear it. Don't know if the newer trailer brakes do this or not but my 2004 and 2008 model trailer wheels do this...

Like said above don't leave the emergency brake switch engaged for length of time. The brakes could be drawing 12 AMPS from your trailer battery which will drain it rather fast. Also 12VDC applied directly to the brake magnets may heat them up pretty quick as well.

Also note the emergency brake plunger is keyed to go back into the switch assy only one way. Both my trailer plungers are pretty hard to push back into place.. It will snap into place when done properly.

Roy Ken

westend wrote:
If you pull the emergency break-away pin it will power up all the brakes. I wouldn't leave the brakes energized for more than a few minutes at a time since the magnets could suffer from the heat.

Your idea of an independent powered lead to each wire set will work, also.

But the OP would have to disconnect the wire to each wheel to do that.
Pulling the break-away pin is much easier and faster!
With each wheel jacked up (or even one side of the trailer) it would be easy to spin each wheel to see if there is an issue.

But it sounds to me that the OP may have a chafed wire which is intermittently shorting to trailer ground. Checking each brake will probably not find that.

If you pull the emergency break-away pin it will power up all the brakes. I wouldn't leave the brakes energized for more than a few minutes at a time since the magnets could suffer from the heat.

Your idea of an independent powered lead to each wire set will work, also.