All Trailer Lights Come on When Brake Is Pressed and All Lights Blink with Turn Signal

Question

Question:

All the light blink on the trailer when the turn signals are turned on. Also alll the lights light up when the brake is applied.

asked by: Tom L

0

Expert Reply:

Your problem is in the wiring in one of two places. It is either on the vehicle wiring harness or somewhere in the wiring on the trailer. The first thing to do would be to narrow it down to one of these two places, then we can pin-point the problem from there.

Disconnect the trailer from the vehicle so you can test the vehicle wiring to see if it is functioning properly. Using a circuit tester, like part # PTW2993, clip onto the exposed ground post, white wire, and check the other three contacts. Brown is taillights and should come on with head lights. Green is passenger side turn signal and brake, and yellow is driver side. If these functions all work properly, then the vehicle wiring is fine, and you can move on to the trailer. If not, then there is something wrong with the vehicle wiring and if you write back with the vehicle year, make and model and whether or not it is a factory installed harness and I could help you further diagnose the problem.

If all the functions one the vehicle connector work fine, then the trailer wiring is probably the root of the problem. The first thing to check is the ground wire, the white wire coming off the connector. A bad ground is a common problem on a trailer and will cause the lights to do all sorts of odd things. Make sure that the ground wire has good connection to the metal trailer frame. Even paint can sometimes prevent a good connection. Check the lights themselves and make sure they are grounded properly.

If you find that a ground is not your problem, then the trailer may be wired incorrectly. You should have 4 wires coming off the connector to the trailer white should be attached to the trailer frame, brown should split somewhere and run down both sides of the trailer to power running lights and taillights, yellow should run down the driver side for brake and turn lights and green down the passenger side for brake and turn lights.

I have included a link to a trailer wiring diagram and a video of a light kit install on a trailer so you can see how the wires need to be run.

expert reply by: Patrick B

0

Devere

4/17/2020

My left signal all the lights work my right signal nothing works

Reply

Chris R.

4/18/2020

Is it just the turn/brake signal on the right side that's not working, or are the running lights not working as well? My first instinct here is that there's a blown fuse under the tow vehicle's hood. Check for any fuse locations in the owner's manual related to those circuits. Let me know what you find and we'll keep troubleshooting (if needed).

Reply

Answer 1

You are correct that the issue is on your trailer and based on what you are describing the circuits are somehow swapped when you installed your connector; unfortunately, I was unable to find your order number to see what you purchased from us for…

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Answer 2

Try improving the connection of the main ground wire of the trailer wiring harness. Make sure it is attached to a clean metal surface. Or you can run all of the trailer wires back to the main ground. This is actually the ideal solution. But you can…

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Answer 3

The most likely cause for the incorrect behavior of your trailer lights, where activating one turn signal causes all trailer lights to blink, is an insufficient ground (or a short to ground) on either the vehicle or the trailer. Since you re-wired…

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Answer 4

When a trailer with electric brakes is connected to a vehicle that has a brake controller that brake controller is sensing the draw of the brake magnets by sending back a small amount of voltage on the blue wire. The brake controller also get's…

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Answer 5

Yes we do. You would want the part #STL22AB for an amber version of the light part number you listed. Another option is the part #STL72AB or part #STL70AB.

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Answer 6

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 7

It sounds like you have a ground issue. When trailer lighting does not have a sufficient ground many different scenarios can show up, but the most prevalent is when the most amperage is applied, like tail lights on and brake pedal pressed, the lights…

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Answer 8

Curt recommends the use of 250 ft/lbs of torque when tightening the nuts of their hitch balls with a 1 inch diameter shank like the part #C40034 that you referenced. The general rule is for a 3/4" shank tighten to 150 ft/lbs For a 1" shank…

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Answer 9

We don't have a combo of the Curt Hitch Ball #C40008 and Curt Ball Mount #C45340. The ball mount is extremely heavy-duty, rated up to 17,000 pounds. I think it's safe to assume you don't have a torque wrench rated up to 450 foot pounds…

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Answer 10

The correct torque for installing lug nuts on your 5 X 8 trailer's 5-lug wheels will depend on the size of the lugs. For a 1/2-inch lug the torque spec ranges from 75- to 85-ft-lbs. For a 9/16-inch lug the torque spec ranges from 135- to…

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Answer 11

The only difference between 7-Way Utility and 7-Way RV is the color of the wires. The pin outs are the exact same so either would work just fine with the other. If you check out the picture I attached you'll see that the functions are all the…

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Answer 12

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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All Trailer Lights Come on When Brake Is Pressed and All Lights Blink with Turn Signal

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