Troubleshooting Trailer Wiring Connections on 2003 Chevy Silverado 4x4

Question

Question:

I think I have a ground problem on the truck side of things...truck didnt come with a hitch so I installed...also installed a plug 7 pin and 4 pin comboplugged into factory harness...I have constant power to yellow..even when truck is off...left directional both flash...right directional work fine...all running lights work...plugged into a buddys truck...everything is perfect...so I know its my truck...where are the grounds located on my truck 2003 Silverado 4x4

asked by: Paul

1

Helpful Expert Reply:

There are multiple ground locations on your 2003 Chevy Silverado 4x4. I don't believe that is your issue since you have the factory wiring harness. I recommend you use a circuit tester like # PTW2993 and test the pin functions of your trailer connector first. If they work with your grounded circuit tester perfectly, then trace your ground wire or create a new connection by splicing in and connecting the frame of your truck bare metal to metal.

If they don't work correctly, then remove your 7-way/4-way combo and test the wiring harness behind it with the circuit tester. Check for bent pins on the connector. If the US Car Connection harness works and there aren't bent pins, then replace your trailer connection with # HM40975.

If all else fails, use the 4-Pole Hardwire Kit with Circuit Tester # 18252 and then Universal Installation Kit for Trailer Brake Controller # ETBC7 to completely hardwire connection or splice into wiring you have confirmed works properly.

expert reply by: Jason S

1

Answer 1

My suspicion is that you have a poor ground connection somewhere on your trailer. The fact that everything works fine until the running lights are turned on is the dead giveaway. When the tail lights are turned on, the trailer lighting is drawing…

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Answer 2

Sounds like you have a blown fuse under the hood of your 2003 Chevy Silverado. The truck will have trailer wiring fuses/relays that are separate from the truck's turn signal fuses. That is why your truck's turn signals are working but…

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Answer 3

What you are describing is normally the result one 1 of 3 issues: First, there could be some corrosion in or on the connectors on the vehicle or trailer side or both. Second there could be a bad ground. Bad grounds can cause all sorts of bizarre…

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Answer 4

What you are describing is normal. When you turn on your headlights the running lights of your trailer should illuminate. The running lights are dimmer than when the bulb is being used as a turn signal or a brake signal. Basically the trailer lights…

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Answer 5

You are correct, you should only be getting output when the brake is applied, or the override switch is activated. It sounds like the controller might be bad, but to make sure, you should probably bench test it before tossing it. Use a circuit…

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Answer 6

Manufacturers can use any colors they want since there isn't really a standard for wire color and function. You will need to test each of the wires using a circuit tester such as #PTW2993 to determine the functions. Then you can attach them to…

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Answer 7

When wiring a trailer connector, it is best to wire by function, as wire colors can vary. We have an excellent wiring diagram on our website, I will provide you a link so you can look at it. If you are looking at the inside of the trailer connector…

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Answer 8

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 9

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 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

It could be a tow package fuse on the vehicle. Use the owners manual to find the locations of fuses/relays related to the tow package wiring to check them and replace as needed. If the issue is not a fuse or relay then you can test the vehicle side…

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Answer 12

You will have to go with a sliding hitch to allow the trailer to make tight turns. For a trailer 8 feet wide the only bed length that's going to allow 90 degree turns without a slider is a stationary hitch. That being said you have two options.…

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Troubleshooting Trailer Wiring Connections on 2003 Chevy Silverado 4x4

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