No Trailer Lights. Which Relay?

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Zen_master
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No Trailer Lights. Which Relay?

Postby Zen_master » Sat Nov 12, 2016 10:30 am

Hooked up the boat expecting to hit the lake this weekend and upon the final step in the process of plugging in the 4-pin connector I discovered I have no trailer lights.

To be clear, this is not a situation where just the running lights are out or a case of no turn signals. It's all the lights including brake lights.

I have another tow vehicle (Jeep) and the trailer lights work when hooked up to that truck therefore eliminating the issue being at the trailer. Further, the trailer lights worked a few weeks prior when towed by the Pathfinder leading me to believe it's a sudden change as opposed to a gradually evolving problem or intermittent issue.

In the engine compartment there are two boxes of relays and fuses. I checked all the fuses and they are OK. But I don't see a visual way of verifying if a relay is defective.

Several of the relays are labeled trailer, such as "trailer left" or "trailer right." I find it hard to believe these are redundant and wish to seek the thoughts of those here as to which one would be responsible for all trailer lights not working when hooked up to the R51.

Not sure if there's any difference between the 6-cylinder version and the V8 but in this case the problem vehicle is a V8.

Please advise if anyone knows which relay is responsible for running lights on the trailer. Thanks in advance.


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Zen_master
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Postby Zen_master » Sun Nov 13, 2016 4:00 pm

Correction. The tail lights on the trailer work when the brake pedal is depressed or the turn signal actuator activated. The parking lights / running lights do not work all the way around including the rear tail lights.

Anyone know which relay is responsible for this?

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disallow
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Postby disallow » Sun Nov 13, 2016 8:30 pm

Have you checked for voltage at the 4 pin connector?

Also, there are hidden fuses under the dash wrapped in electrical tape.

I've had issues with my harness going to the connector, which can cause a short and cause fuses to pop.

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smj999smj
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Postby smj999smj » Mon Nov 14, 2016 3:40 pm

I believe the fuses wrapped up under the dash were only on 2005 models. There was a subharness installed per a TSB to rectify a problem and corrected by the 2006 and later models if I'm not mistaken.

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Postby Zen_master » Sat Dec 17, 2016 12:11 pm

Thanks, smj. Had to re-tap the holes to clear the oxidation. You are correct. M8x1.25 is the proper fitment

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Zen_master
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Postby Zen_master » Sat Dec 17, 2016 2:42 pm

Spoke with a few folks in the automotive industry and was told it is quite rare for a relay to go bad. Recommended swapping out suspect problem relay with the horn relay to check if the relay is bad. Low and behold the Pathfinder uses a different relay for the horn and Tow Relay 1.

I've checked the fuses per the owner's manual and I cannot find one that is blown. To be clear, I'm only looking under the hood and the fuses in the glove box. I was not able to locate any under the driver's side dash. Vehicle is 2011 V8. Not sure if this makes any difference.

I have brake light and turn signals but no running lights at all. All trailer lights work on another vehicle so the problem is the Pathfinder, not the trailer.

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smj999smj
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Postby smj999smj » Sat Dec 17, 2016 6:32 pm

There is a fuse panel when you open up the glove box, but I'm not sure if there is fuse for the trailer lights there.

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Zen_master
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Postby Zen_master » Tue Jan 10, 2017 7:55 pm

Checked all the fuses with anything marked "trailer." Most say it's rare for a relay to go bad. Sounds like a trip to the stealership is in order. Silver lining is it is winter and because I'm not hauling the boat at all these days I'm in no hurry to deal with their BS.


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