Trailer Turn Signals Both Blink when Just Left Turn Signal is Activated

Question

Question:

all the trailer lights work fine until i hit the left blinker then the back two trailer lights start to blink as if i turned the hazards on

asked by: Hayden

0

Expert Reply:

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 things to happen as electricity likes to take the path of least resistance. And third, sometimes wiring mistakes can be made if the trailer connector is a wishbone type harness (4-Way flat but with 5 wires coming out, 2 for running lights).

First disconnect the trailer and use a circuit tester, like # PTW2993 if you do not already have one, to test the vehicle side connector for the proper functions. I have included a link to a video that explains how to test a converter along with an FAQ article on troubleshooting 4 and 5-Way wiring.

On the trailer side you will want to make sure the connector is clean and that the main ground is connected to a clean and corrosion free bare metal surface. You will also need to do the same for each of the trailer lights. Also if the trailer has an aluminum frame, tilt bed, or folding tongue then it will help to run jumper grounds from the lights to the main trailer connector ground.

expert reply by: Michael H

0

Dan T.

5/10/2020

I have the magnet type lights for my car trailer i have the 4wire plug everthings is working good until i turn on my turn signal both lights blink i have move the ground3 times on my truck with the same result i could use some help.

Reply

Chris R.

5/13/2020

I would start by testing the 4-Way connector on your tow vehicle. Use a circuit tester on the turn/stop circuits while they're activated on the vehicle - see if you get power on both turn/stop circuit pins with just one side activated. If so, this means the issue is somewhere on the vehicle side. In this case you will want to visually inspect the 4-Way for any corrosion/debris built up inside the pins, cleaning out as needed, and check the wiring right behind it for any exposed or pinched sections that need to be repaired/replaced. Let me know what you find and we'll go from there.

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Kevin

3/25/2024

@ChrisR I have the same issue. I ran all new wiring and lights. I even bought a new adapter from the 7 to the 4. I do know when I turn the right one on it works but lacks power to feed the side bulb

Reply

Glen B.

10/28/2024

Hopefully I can explain this, I'm making a trailer out of a pop-up camper that was damaged in a storm. I'm trying to use the 7pin wiring harness that is on the trailer, the wiring going to the rear lights I have installed is just 3 wires, green, brown and red. I have tied into the brown wire to run over to the right turn signal. I have the green and brown going to the right turn signal and the red and brown going to the left turn signal. Both lights blink one Way and no light the other way. I turn on the headlight and just one rear light turns on. Any suggestions? Thanks Glen

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Bryce D.

10/28/2024

@GlenB Hey Glen. can you go ahead and send a few pictures over to [email protected] so I can get a look at what you're working with?

Reply

Anwar

11/2/2024

Hi sir, I just brought pop up camper. The seller cheat me.he said everything ok but when I toe it with my car the left and right signal does not work separately. When I turn left signal and right also work. But I turn right signal, the left does on. So right signal work ok but with left, right also start blinking. Please advise, I will be grateful to you.

Reply

Robin H.

11/3/2024

@Anwar try checking the ground to make sure it is secure. If it is, work your way along with a tester while running the turn signal until you find where the power crosses over. I would start with the vehicle connector and if that checks out work your way back on the trailer.

Reply

Anwar

11/3/2024

@RobinH Hi Sir, thank you very much for your instant reply. Really appreciated. Sir, I am new in camping and don't know too much about electronics. I will be grateful if you please also share details. I can send you the video of issue if you want by email. Actually seller cheat me and he give me faulty lights but he get full money what he asked for everything working.

Reply

Robin H.

11/3/2024

@Anwar if this isn't something you're familiar with and you think the seller cheated you I really recommend taking it to a local shop to have them look it over. You don't know what else might be wrong with it and you don't want to find out while you're out in the middle of nowhere.

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See All (6) Replies to Anwar ∨

Answer 1

If both turn signals blinking at the same time is a new problem that has occurred after the harness had worked fine before, there are a couple of possibilities that may be causing the issue. First, the easiest thing to check are the trailer…

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Answer 2

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 3

You will first want to check the fuses on your tow vehicle. Some vehicles could have fuses for operating the turn signals and brake lights of a towing package. You will want to check if they are installed and working properly. The next thing is to…

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Answer 4

Hi Bruce! We definitely have what you are looking for. I have just the wheel and the same wheel with a pre-mounted tire listed below: Dexstar Conventional Steel Wheel with Offset - 13" x 4-1/2" Rim - 5 on 4-1/2 - Black #AM20214 Loadstar…

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Answer 5

The 20 Ft 4-Way Trailer Wiring Harness - Wishbone Style - 30" Ground #A20WB simply has two wires that connect to the running light pin of the 4-way. There isn't a 5 wire we carry in spools or by the foot, but we do carry the Bonded 4 Wire -…

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Answer 6

You should be getting 12 volts on the running light circuit when the running lights are turned on. If not, the problem is either in the connector or upstream from there. The first thing you should check is the trailer connector on your towing…

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Answer 7

The cause of both turn signal lights flashing together would almost certainly be attributed to a poor ground. There are several grounds you will want to check which include one for each light, the trailer side trailer connector and the vehicle side…

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Answer 8

The closest LED option that we have to your Monarch #5237 tail lights is the Optronics LED Trailer Light Kit #TLL160RK. These measure 2-7/8" tall, 8-1/16" wide, and 2-13/16" deep. The kit will fit as far as depth goes, but they are…

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Answer 9

If your right turn signal is blinking with the left turn signal applied that most likely means you have a short between the right turn and left turn signal circuits or you possibly have the left turn signal shorted out to the running light circuit as…

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Answer 10

Hi Larry, If the indicator light is constantly on then it's likely just the placement of your reed switch on the air cylinder itself. The reed switch detects magnets and closes the circuit, sending power to the indicator light. Try moving it…

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Answer 11

In order to add a trailer connector to a fifth wheel trailer for triple towing you'll need a harness for which I recommend the 4-Pole Hardwire Kit with Circuit Tester part #18252. This kit comes with a circuit tester which you'll need to use…

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Answer 12

The wheel you are looking for is the part #AM20304 as it is 14 inch in diameter, 5-1/2 inch wide, can have a baby moon cover installed on it like #AM90086 and it's pilot diameter is 2.62 inches.

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Trailer Turn Signals Both Blink when Just Left Turn Signal is Activated

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