7-Way Trailer Connector Wiring With No Identifying Wire Markings

Question

Question:

My utility has 7 wires but 4 colors. 3 brown 2 with yellow stripe, 2 yellow, 1 green and 1 black. It was connected to 7 pole that plugged into my truck 7 pole. Wiring got ripped out of pole. I had to by new pole for my utility but it has 7 colors. Not sure how to match. I have not seen a color diagram of wire colors similar/like my utility trailer on the internet. I can get all lights to work but trailer running lights. I can continue to trial and error but becoming time consuming. Have any ideas. Thanks,

asked by: Shawn B

0

Expert Reply:

I would begin by using a small 12 volt battery to start isolating the wiring. First you will want to trace the wiring to determine which wire is the ground wire. It should be grounded to the frame. Connect the ground to the negative battery terminal.

Begin placing each wire individually to the positive terminal and identifying what each wire operates. Once you have identified the wires I have included a wiring diagram for both the trailer and vehicle sides so that you will be able to use a Circuit Tester # PTW2991 to test the truck circuits as well if you are still having issues.

expert reply by: Bud M

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Trailer Side 7-Way Wiring
(click to enlarge)

Vehicle Side 7-Way Wiring
(click to enlarge)

Answer 1

No you should not have constant power on the brake output pin, the blue wire should only have power with the brake pedal depressed in the vehicle or the brake controller manual override is activated. If the blue wire has a constant 12V then it is an…

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Answer 2

We definitely have options available to add a brake controller to your 2002 Chevy Silverado C3500. You may need an extra part depending on if it came with a 7 Way from the manufacturer or not, but I have a good option for that as well. With that…

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Answer 3

There could be in internal short in the brake controller. Use a circuit tester like part #PTW2993 on the blue wire exiting the rear of the controller. There should be no voltage on that wire unless the brake pedal is pressed, or the manual brake…

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Answer 4

Thank you for being very detailed with your question! The first step I would take is to make sure everything on the truck and trailer is wired properly. Your Prodigy brake controller should have the wiring adapter #3025-P which is custom for your…

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Answer 5

If your trailer brakes activate when using the manual override but not when pushing on the brake pedal you may have a bad connection or a faulty brake switch. I have also linked below our article on Brake Controller Troubleshooting. Also if you have…

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Answer 6

There are many things that can affect the voltage on the brake output wire from your brake controller to your trailer brakes such as the power setting on your brake controller, how you are testing the wire and if you are testing it with the brakes or…

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Answer 7

The humming sound you hear from your trailer's electric drum brakes is a good sign. It means that the brakes' magnets are being energized by the output from the trailer brake controller in the vehicle. The issue with the brakes not applying…

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Answer 8

A 4-Way trailer connector has the basic lighting functions only; running lights, left turn signal and brake lights, right turn signal and brake lights, and ground. A 7-Way has these functions and a 12 volt circuit, a circuit for electric trailer…

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Answer 9

The difference between the Class II and Class III hitches has to do with their Gross Trailer Weight (GTW), their Tongue Weight (TW), and their Hitch Receiver Size. Class II trailer hitch receivers have a 1-1/4 inch receiver and can be rated up to…

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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.

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Answer 11

We have run into this quite a few times in the past, and the best option will be replacing the Lance 7-pin connector with a standard 7-way blade connector like the #PK12706. This will give you a standard 7-way connector to plug into the factory 7-way…

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Answer 12

Installing the Union Tee #AL21838 with your #AL57575 will tie the pressure of the two air bags together. So yes, a shift in a very heavy load like a truck camper will potentially result in air being forced from one into the other. The reason I say…

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