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bigrockk · 03-24-2019, 09:50 AM

If you are comfortable doing some electrical troubleshooting it should be fairly simple to do a little testing to at least point you in the right direction.

To make this easy you really should have a meter with a DC amp clamp such as the UNI-T UT210E. This is an excellent meter for the price and super handy for testing DC circuits, just Google it, you will find it on eBay or Amazon for around 50 bucks.

The first thing I would do is plug the trailer into the truck. Then find the easiest place to get the “amp clamp” around the wire that supplies current to the trailer brakes. (I think it is the #2 pin on the 7 pin connector but you can Google to confirm)

Now the magnets at the brakes vary somewhat in the current that they draw depending on the model so you can look that up for your particular model, but I think on average they draw between 3-4 amps per wheel.

So with the truck running, brake controller set to max have someone step hard on the truck brakes and hold them there while you read the DC current at the meter, if the current is slowly rising keeping reading the meter until the current stabilizes. If the reading stabilizes at around 12-16 amps chances are the electrical is ok and the braking problem is mechanical.
Keep in mind this doesn’t rule out an intermittent electrical problem 100% but it’s a good starting point to figure things out. If the current is well below the combined rated values of your braking magnets then it is very likely the problem is electrical.

All of this isn’t conclusive but it’s a good starting point to knowing what is going on. Hope this helps and makes sense. Good luck and post back your results and maybe we can help some more if need be.

03-24-2019, 09:50 AM	#28
bigrockk Member Join Date: Jul 2010 Location: Wpg Posts: 51	If you are comfortable doing some electrical troubleshooting it should be fairly simple to do a little testing to at least point you in the right direction. To make this easy you really should have a meter with a DC amp clamp such as the UNI-T UT210E. This is an excellent meter for the price and super handy for testing DC circuits, just Google it, you will find it on eBay or Amazon for around 50 bucks. The first thing I would do is plug the trailer into the truck. Then find the easiest place to get the “amp clamp” around the wire that supplies current to the trailer brakes. (I think it is the #2 pin on the 7 pin connector but you can Google to confirm) Now the magnets at the brakes vary somewhat in the current that they draw depending on the model so you can look that up for your particular model, but I think on average they draw between 3-4 amps per wheel. So with the truck running, brake controller set to max have someone step hard on the truck brakes and hold them there while you read the DC current at the meter, if the current is slowly rising keeping reading the meter until the current stabilizes. If the reading stabilizes at around 12-16 amps chances are the electrical is ok and the braking problem is mechanical. Keep in mind this doesn’t rule out an intermittent electrical problem 100% but it’s a good starting point to figure things out. If the current is well below the combined rated values of your braking magnets then it is very likely the problem is electrical. All of this isn’t conclusive but it’s a good starting point to knowing what is going on. Hope this helps and makes sense. Good luck and post back your results and maybe we can help some more if need be.