Issues with the trailer brakes, going to rewire.4 drums. Original setup has a set of two wires running to each drum.Going to run one Marine grade coated wires for 2 drums, instead of all 4.My question is where is the best place to ground all the drums?One ground per drum on frame?Ground all four at the junction box with truck and trailer?Thank you for your time

One wire is for 12 volt power to the brake magnets and the other wire should be grounded either to the trailer frame or to the main trailer ground wire. It does not matter which wire is used for power or ground because they are not polarized. I prefer individual grounding vs junction boxLoose a ground and only one brake is affected vs ALL brakes

I ran one pair of wires per drum and led them all forward to a terminal strip. That makes any future problem diagnosis easier to accomplish. You can ground the (-) phase of the brake wiring to any clean frame point. The size of the steel in the frame will preclude any large voltage drop from resistance in the circuit. If you do choose to ground each (-) brake wire, individually to the frame, you will have six (6) 12V frame ground points to maintain, four from the brakes, the battery's frame ground, and the ground from the towing connector umbilical.

westend wrote:I ran one pair of wires per drum and led them all forward to a terminal strip. That makes any future problem diagnosis easier to accomplish. You can ground the (-) phase of the brake wiring to any clean frame point. The size of the steel in the frame will preclude any large voltage drop from resistance in the circuit. If you do choose to ground each (-) brake wire, individually to the frame, you will have six (6) 12V frame ground points to maintain, four from the brakes, the battery's frame ground, and the ground from the towing connector umbilical.I like this way. One location near the front of the trailer. Still have connections at all four drums, but the ground is in one place.

Vintage465 wrote:...One location near the front of the trailer. Still have connections at all four drums, but the ground is in one place.Redundancy of multiple grounds insures the system operates when needed. With one ground, if it is lost, none of the brakes work at all.

Rewiring trailer brakes, best place to ground them?

12 Replies

westend
Explorer
Nov 28, 2017
I ran one pair of wires per drum and led them all forward to a terminal strip. That makes any future problem diagnosis easier to accomplish.

You can ground the (-) phase of the brake wiring to any clean frame point. The size of the steel in the frame will preclude any large voltage drop from resistance in the circuit. If you do choose to ground each (-) brake wire, individually to the frame, you will have six (6) 12V frame ground points to maintain, four from the brakes, the battery's frame ground, and the ground from the towing connector umbilical.
Old-Biscuit
Explorer III
Nov 28, 2017
One wire is for 12 volt power to the brake magnets and the other wire should be grounded either to the trailer frame or to the main trailer ground wire. It does not matter which wire is used for power or ground because they are not polarized.

I prefer individual grounding vs junction box
Loose a ground and only one brake is affected vs ALL brakes

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Rewiring trailer brakes, best place to ground them?

12 Replies

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