Testing Trailer Brake Magnets When Brakes Are Not Working

Question

Question:

1982 Chevy K10 Blaze, I have power from brake at seven way to trailer, want test magnets and wiring to each of four brakes in my trailer.

asked by: William H

0

Expert Reply:

The first test you will want to do is to test the amperage of the trailer braking system with a multimeter, like # PT89ZR. First, you will connect the ammeter inline with the blue wire exiting the back of the brake controller. Check the amperage. If the amperage is greater than the maximum amount listed in the attached chart, you will want to replace the magnets. For a trailer with 4 brakes and 10 or 12 inch drums, the maximum amperage at 12-13 Volts should be between 15.0-16.3 amps. For 4 brakes with 7 inch drums, the maximum amperage should fall between 12.6-13.7 amps.

If this test shows the amperage at a normal measurement, you can begin testing the individual brake magnets for proper amperage. You will also want to test the magnets for a short and for resistance. I have attached a help article on testing trailer brake magnets for you.

expert reply by: Victoria B

0

Answer 1

It depends on what the brake controller output is set to. If you have the brake controller set to the maximum then there should be about 12 volts at the brake magnets. To see if the brake magnets are drawing the correct power set the brake controller…

view full answer...

Answer 2

Its not uncommon for there to be slight voltage drop off over a certain distance but with the brake controller set to the maximum you should still be getting 12 volts at the brake magnets. We need to determine if the low voltage is coming from the…

view full answer...

Answer 3

Testing your trailer brakes for proper function on the test bench will require a multimeter that can display readings for both amps and ohms, such as part # PT89ZR. (Some brake controllers, such as the Tekonsha P3, have built-in test functions.) You…

view full answer...

Answer 4

If you are only getting 1.5 volts at your brakes then there is an issue, but there is not a fuse that controls the brakes. There are a number of possible issues so you will need to find out if the issue is on the brake controller, truck, or trailer.…

view full answer...

Answer 5

It should be getting close to 12 volts if the power output is set to the maximum on the brake controller. Some brake controllers will not work properly if they are titled or turned to the side or if it has a leveler knob that is not level. Check…

view full answer...

Answer 6

First, do a visual inspection. You should make sure that the front of the magnet is not worn to the point where the interior copper windings are visible. Also, check the armature surface (inside rear of brake drum where magnet rides) is free of…

view full answer...

Answer 7

I believe you almost solved the problem when you swapped the wiring, but in reality you needed to use 10 gauge wire like part #10-1-1 (sold by the foot). You are experiencing a voltage drop due to the long distance of wire that's not thick…

view full answer...

Answer 8

I do not recommend that you bypass the break away system because in many states it is a requirement to have a working break away system. Trailer brake magnets will have one power wire and one ground. The power output from a break away system will go…

view full answer...

Answer 9

Yes. There should always be a very light power on your brake controller wire. However, it should be extremely minimal. As you increase in power using the manual override, you should see an incandescent circuit tester like #PTW2993 going from almost…

view full answer...

Answer 10

In order to determine the torque rating for the lug nuts on your trailer you will need to know check out the chart I attached that shows all of the torque specs for all the trailer lugs available based on stud size, wheel material and wheel size.

view full answer...

Answer 11

Either way is correct. It depends on if you want to keep the semi-style 7-Way (if you need to tow that type of trailer) or if you will never be towing a semi-trailer. If you need to keep the 7-Way semi active on the truck, then you would need to make…

view full answer...

Answer 12

I think you are going in the right direction. I would definitely replace the 14 gauge wire going to the trailer brake magnets with 10 gauge wire or larger. Usually larger than 10 gauge is hard to get into the trailer connector though. I would also…

view full answer...

Testing Trailer Brake Magnets When Brakes Are Not Working

Products Referenced in This Question

Product Page this Question was Asked From

Featured Help Information

Instructions

Miscellaneous Media

Continue Researching