How to Bench Test Electric Trailer Brake Assemblies and Magnets

Question

Question:

what would be the proper way to bench test electric trailer brakes? This means the actual brake is not connected to the trailer hub and it is in the shop on the bench.. Any help would be great.

asked by: Lance

1

Helpful Expert Reply:

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 will also need a 12V battery.

Please refer to the linked article concerning the testing procedures for electric trailer brakes. This article includes a table of the correct current values you should read for various sizes and numbers of trailer brake assemblies. It also includes similar data for the resistance values you should read when testing an individual brake magnet for shorts.

expert reply by: Adam R

1

Answer 1

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…

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Answer 2

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…

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Answer 3

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…

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Answer 4

The biggest difference between an Equal-I-Zer friction style sway control and a system like a Reese Dual Cam High-Performance Sway Control #RP26002 is that the friction style is passive and the dual cam is active. What is meant by that is that the…

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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…

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Answer 6

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.…

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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…

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Answer 8

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…

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Answer 9

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…

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Answer 10

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…

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Answer 11

Are there any visible signs of wear on the magnets like exposed windings then that would indicate they need replacing. Magnets can go bad without showing visible signs of wear though. To see how to troubleshoot them check out the help article I…

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Answer 12

Since you are not getting the 12V power when your truck is running, you most likely don't have a fuse issue as you stated their isn't a specified fuse or relay in the owners manual. The issue is that your truck is computerized even at the…

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