# Trailer wiring problem



## 2006Frontier (Sep 13, 2006)

Hi,
I have a problem with my trailer wiring, the turn signals and the brake lights work OK, but the 
running lights or parking lights are not coming on, I went all the way to the factory connector, under the truck bed, and there still no power.
Is there a fuse some where that I missed, I checked all the fuses in the engine compartment and they are all OK, what am I missing.

Thank you.


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## formula (Jun 16, 2006)

Does your truck have a factory tow package? If it does, you can get a tester to plug into your connector on your truck to check for problems. I had an 05' before I got my 06' and U-haul installed my hitch and wiring. They didn't install the relay that comes with the factory kit and I had alot of problems with my trailer lights working correctly.


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## 2006Frontier (Sep 13, 2006)

Yes, my 2006 frontier has the factory wiring, but the dealer tells me that I need a relay or relays, the dealer says to check on the passanger side kickboard or under the dashboard on the driver side to see if the relays are there, if someone knows please let me know what I need or what the dealer is talking about. Thank you


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## Cusser (Apr 16, 2004)

Can't you just strip back one of the wires going to the taillights and solder in a jump wire to your wiring connector at the truck end? If you get voltage there, then trailer lights will work if that's hooked up OK. A $2 test light will help you diagnose and find wires for this.


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## formula (Jun 16, 2006)

You can go to courtesyparts.com and look up the wiring harness for trailer lights. It has the installation instructions online and you can see the relays. I would think if it had one on from the factory though that it would have the relays. Like I said though, my 05' didn't have the relays and I had problems all the time with my trailer lights. The factory wiring harness for a 4-pin is about $50 and for a 7-pin it's about $65. It comes with the relays and everything you need.


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## Z_Rated (Apr 29, 2006)

Going by an '05, you should have two sets of relays. One near the driver rear under the bed and another in the front passenger kick panel which may be tucked up high and wrapped in foam tape. I'll try to find a diagram. Z


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## Z_Rated (Apr 29, 2006)

Note: for an '05 7 pin RV


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## Z_Rated (Apr 29, 2006)

Part #999T8 BR000 for '05 and '06 7-pin are the same so previous post should apply according to Courtesy Nissan. Hope that helps, Z


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## airse (Sep 18, 2006)

*Quick Fix*



Cusser said:


> Can't you just strip back one of the wires going to the taillights and solder in a jump wire to your wiring connector at the truck end? If you get voltage there, then trailer lights will work if that's hooked up OK. A $2 test light will help you diagnose and find wires for this.


This was an easy fix that worked for me on my 05 LE 4x4. I removed the two bolts holding the left rear tail light assembly in, popped out the running light bulb and with the test light found the Gray wire was the one I was looking for. Then went under the left rear of the truck and found the gray wire again stripped and soldered the jumper wire, went over to my trailer wires and located the running light wire in my case it was a brown one soldered the jumper wire and presto Running Lights!! (The dealer wanted $77.00 for the relays)

I Goggled 05 Frontier trailer light problems and found this forum it is very informative and useful site. Now I am a newbie in your forum.

Thank You all


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## ChuckFrontier06 (Jul 25, 2006)

_*The dealer (Nissan) parts are manufactured for the proper operation of your trailer lights when you are towing. There is no need to cut and splice any wires that can bring trouble in the future. Since the brake lights and turn signals are on seperate circuits, they use the plug and play relays to make sure everything works well without any chance of overloading a circuit. Just my 2 cents.*_


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## scuba91ta (Aug 19, 2005)

You should NOT be cutting and splicing wires. 

1) The system has a dedicated ciurcuit for the trailor lights and trailor brakes for a reason. With the trucks brake light circuit (a light load circuit) powering the trailor brakes and the trailor brake lights, you will overload the circuit, possibly blowing a fuse (hopefully) or worse, starting a fire. 

2) There is a TSB concerning a body control module that needs to be replaced by the dealer. Research this on nissanhelp.com under TSB. This module has to be replaced due to a possibility of a fire if the trailor brake wiring on the trailor is faulty. 

3) 77$ is a lot less than the 500 or 1000 dollar deductable you'd have to pay... worse if it's financed without gap insurance.

Nissan made a dedicated loop for the trailor side of things to isolate issues with the electrical system. It's very important that it be done right. Obviously, those of you who tow a boat trailor and just use lights, it's not a huge issue, as 4 more bulbs in the system are certainly within tolerance. But if you are powering trailor brakes, you better have it done right.


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## 2006Frontier (Sep 13, 2006)

Guys thank you for all your help,
I went to the Nissan dealer and I bought the trailer kit for $60.00, it included 3 relays, 2 harneses and some hardware along with the instructions, I installed it it was a breeze and it works fine.


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## Z_Rated (Apr 29, 2006)

Good news and a wise choice in my opinion. Enjoy, Z


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## mrwzrd5 (Jun 4, 2014)

I have a 2003 Nissan frontier crew cab. it has factory 4 pin wiring harness for trailers I took it to uhaul to have a 7 pin harness put in and now my electronic ignition fuse keeps blowing. which also controls my windows and alarm system


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## smj999smj (Jan 1, 2006)

If it happened since U-Haul installed the 7-pin connector, I would take it back to them and make them fix it!


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## mrwzrd5 (Jun 4, 2014)

I took it back to a different uhaul and they fixed it temporary they found the first uhaul punctured the main wiring harness for the truck. So now I have to file a claim with u haul to get them to replace my wiring harrness. Thanks for the help.


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## amsafetyc (Jun 7, 2014)

*trailer plug wiring no running lights, reverse or 12 v power to the 7 pin*

I have a 2005 Frontier Nismo, in the past Ive installed the 3 relay harness and things were going well for towing. Recently I changed the 4 pin system to a 7 pin system on my utility trailer to match the 7 pin plug on the truck and that's were the trouble began. The first thing that happened was the entire plug went dead and no power at the truck side, after changing all the relays in the passengers side kick panel and one burned fuse under the dash above the brake pedal, I now have 4 ways and directional but still no reverse light, running (parking lights) and no power to the battery leg at the truck side connector. 

I have no ideas as to where to look next and relays are costly items. Is there another location i need to look at or address? I look forward any assistance and suggestions you may have to resolve the issue and get back to a fully functioning 7 pin system.

Thanks

John


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## amsafetyc (Jun 7, 2014)

I have a 2005 Frontier Nismo, in the past Ive installed the 3 relay harness and things were going well for towing. Recently I changed the 4 pin system to a 7 pin system on my utility trailer to match the 7 pin plug on the truck and that's were the trouble began. The first thing that happened was the entire plug went dead and no power at the truck side, after changing all the relays in the passengers side kick panel and one burned fuse under the dash above the brake pedal, I now have 4 ways and directional but still no reverse light, running (parking lights) and no power to the battery leg at the truck side connector. 

I have no idea as to where to look next and relays are costly items. Is there another location I need to look at, investigate or address or a diagram I can trace to identify the origin of those pins to trace back to locate the source? Any assistance and or suggestions you may have to resolve the issue and get back to a fully functioning 7 pin system.

Thanks

John


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## amsafetyc (Jun 7, 2014)

My apologies for the redundant posts, I wasn't sure the first one went through when I posted the second one. This thing has got me really out of sorts trying to figure out why no power on certain pins. I been looking for a wiring diagram of the trailer circuit to no avail so I have no way to trace the system back and take it step by step.


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## tjchis01 (Jul 19, 2014)

Hi everyone. I have the same issue with my 2009 Frontier wiring. I have the dealer supplied wiring harness with the relays already installed, and recently my running lights for the trailer stopped working. Brakes and turn signals fine, and the truck lights all work find, so I think its a relay gone bad needing replacing? 
Any help is appreciated.


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## manmo (Dec 21, 2014)

tjchis01 said:


> Hi everyone. I have the same issue with my 2009 Frontier wiring. I have the dealer supplied wiring harness with the relays already installed, and recently my running lights for the trailer stopped working. Brakes and turn signals fine, and the truck lights all work find, so I think its a relay gone bad needing replacing?
> Any help is appreciated.


If you find out the reason I would like to hear it. I have same exact problem. Turn light on trailer worked once but now I don't get any current in 4pin outlet at truck. Not sure what is wrong. Its hard to replace costly relays without knowing it for sure.

any fuse or something?


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## ALBERTJORETT (May 1, 2016)

my 2005 nissan frontier came with a tow package. i have never used it. bought a camper and i can ot get the lights to work. checked with another vehicle and the lights on the camper do work. do i need an addiitional part for the lights to work or can you give me some suggestions on what to do?


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