Wiring for trailer lights

[Nanph]

I just had our trillium 4500 rewired because we couldn’t get any lights working. I went to pick it up and still, nothing is working.
Here is what I’m dealing with- Our Subaru has a 4 pin which works on our 1300. Our 4500 is a 7 pin so we bought a 7 pin adapter which has worked on a pop up. When we had the 4500 rewired I had them repair the electric brakes for future use. Our Subaru doesn’t have electric brakes though. When we plug the trailer 7 pin into the Subaru 7 pin adapter there is no response. I can’t figure it out. I bought another adapter thinking that maybe it was broken but still no lights. I’m wondering if the electric brakes being set up on the trailer is interfering with a car that doesn’t have the electric brakes option.
Has anyone ever experienced this or have some other ideas for us. I am stumped!

[Darwin Maring]

Check the ground.
Also, Take a battery and test from the connector. Attach negative of the battery to the negative pin of the trailer connector then one at a time the + to each light connector one at a time. Leave the tow vehicle oit of the equasion.
Once you prove the trailer wiring is ok then move on to the tow vehicle.

[Darwin Maring]

Here are some must haves:
https://www.harborfreight.com/four-w...g_q=test+light

https://www.harborfreight.com/electr...ster-4288.html

https://www.harborfreight.com/7-func...g_q=multimeter

With these devices you can troubleshoot your wiring on the tow vehicle and the trailer.

[jimknoch]

Originally Posted by Nanph

I just had our trillium 4500 rewired because we couldn’t get any lights working. I went to pick it up and still, nothing is working.
Here is what I’m dealing with- Our Subaru has a 4 pin which works on our 1300. Our 4500 is a 7 pin so we bought a 7 pin adapter which has worked on a pop up. When we had the 4500 rewired I had them repair the electric brakes for future use. Our Subaru doesn’t have electric brakes though. When we plug the trailer 7 pin into the Subaru 7 pin adapter there is no response. I can’t figure it out. I bought another adapter thinking that maybe it was broken but still no lights. I’m wondering if the electric brakes being set up on the trailer is interfering with a car that doesn’t have the electric brakes option.
Has anyone ever experienced this or have some other ideas for us. I am stumped!

In order for your electric brakes to work on the trailer, you will need a brake controller. There are various types, but each will send a 12Volt DC pulsed signal to the trailer brakes to engage to a varying degree, either based on the deceleration of the tow vehicle, or a simple timer to trailer brakes full on when the tow vehicle brakes are engaged.



Get yourself a 12V test light and you can check to see just what is hot and what is not hot with varying things turned on in the tow vehicle. I would start the testing with the lights. Measure from the metal chasis to each pin on the plug until you determine which is associated with the running lights. Next, I would test for pin location for the left turn flasher, then the right turn, finally, I would check for the tow vehicle brake lights (also usually the emergency flasher). Once you have verified everything on the tow vehicle to the connector, plug the trailer into the connector and go through the test again using the trailer as the test light. One last thing to check is the ground connection between the trailer and the tow vehicle. If you tested the trailer without having the trailer connected to the towball, put a jumper cable from the ball to the tongue of the trailer and try it again. I believe the 4 pin connectors do not have a ground connection so this may be the root of your problem.


Good Luck with the testing! ....... Jim

[thrifty bill]

Other than some pickup trucks, I'm not aware of vehicles coming with a factory brake controller. Its pretty much an after market install.

If you have access to another car with trailer set up, hook up the trailer to that one. At that point, you will know if it is trailer or your car.

[Radar1]

If you have a voltmeter you can check to see if there is voltage through the correct pins on the adapter. You should be able to get voltage on the taillight pin and both turn signal pins.
When we connected a 4 pin to our 08 Outback, we needed a special powered connector to ensure enough voltage got to the trailer lights, and then added the 7 pin after that (running the three extra wires ourselves).
Having electric brakes on the trailer shouldn't affect the tail lights or turn signals, unless they wired the trailer incorrectly.

[Nanph]

“we needed a special powered connector to ensure enough voltage got to the trailer lights, and then added the 7 pin after that (running the three extra wires ourselves).”
This may be what we need. Where did you get the connector? We’ve checked the power using the tools suggested and everything seems to be coming from the the vehicle and out to the 7 pin but the trailer lights still aren’t working.

[Nanph]

Thanks for the suggestion Darwin. We headed to princess auto this weekend and picked those pieces up. Everything seems to be working from our end, so we’re still flummoxed as to why the newly wired trailer is not cooperating.

[Radar1]

The powered connector we got for our Outback was from etrailer.com.
It's possible that whoever connected your 4 pin plug to the Subaru may have used the correct powered adapter, so if they did, then it seems the problem is in the trailer wiring which the test tools mentioned earlier can help trace.

[Nanph]

Thank you for everyone’s help. I’m heading back to the Rv shop tomorrow and hopefully we will leave there with working lights.

[Joe MacDonald]

Can you clarify please, does nothing work, or is it only the brakes not working.
To make the brakes work there has to be a brake control somewhere in your tow vehicle, even if it’s one of the new wireless ones, otherwise the lights should work, but that’s it
Joe

[Nanph]

There was nothing working when we went to pick it up from the shop after being repaired. The employee at the rv store told us that it was an error on our end. After problem solving with the suggestions above we went back to the RV store and lo and behold it was working! I suspect that he went back to check his work after we left. Now we have it back at home but none of the 12v lights are working. I won’t be going back to that RV place. 😊