Trailer running lights not working since day 1, dealer won't help...DIY fix?!?

Justin311 · 05-14-2006, 05:48 PM

EDIT: I found a "hidden" blown fuse (Trailer Tow) and now only the driver's side taillight works, passenger is still out. See post #2.

My trailer running lights on my '04 CC w/ Big Tow haven't worked since I first got my truck almost 2 years ago. For the first year I assumed it was my trailer (old and beat up) then I got a new trailer....still don't work. Hmmm. I checked this board and saw other people have had problems, but usually its people without the factory towing package. I double checked all the relays and they're there.

So I figured I'd try the BCM replacement TSB first. I told the dealer up front "running lights don't work and never have, please make sure ALL lights are working when it leaves!" and he said no prob, that was part of the TSB to fix.

So I get it back and he tells me it has all been double checked. Well guess what...no trailer lights. So I got out the test light and checked at my trailer adaptor. Using the test light shows that both blinkers, hazards and brake lights all work fine. But nothing when just the headlights (running lights in back) are on.

I am about to take it back to the dealer again but I have the feeling they will say its fine and not fix it.... I'm planning to tow a distance on wednesday so I need it fixed before then. Add to that I'm at 39k miles so technically I don't think the lights are still under warranty, so if I get in a pissing match with teh dealer I'm sure they'll win

Can anybody help me figure out whats going on?!?

Justin311 · 05-14-2006, 06:32 PM

OK so I kept searching and on the FOURTEENTH page (LOL) of posts I finally found one that describes my problem:

Trailer Running Lights

It instructs to replace the 10A fuse in the "hidden" rearward fuse box. The fuse is labeled "trailer tow", and was blown on my truck. So I replaced it...and now my lights HALF work

(better than none).

The driver's side light works but the passenger side is still out (this was verified with a test light at the trailer adaptor).

This HAS to be a BCM issue, as this same light works for the turn, hazard and brake lights, and now the proper fuse has been replaced. Any help?!?

scr38 · 05-14-2006, 06:56 PM

It is not a BCM problem. There is one wire to the trailer for the running lights. If one tail light works and the other doesn't, it is a trailer wiring problem or a bad bulb/socket. The brake, turn and hazard use the same section of the bulb. The tail is a seperate element.

Justin311 · 05-14-2006, 06:59 PM

Ahhhh....that makes sense.

Going to check the bulb.

Justin311 · 05-14-2006, 07:07 PM

Nope, not the bulb. I pulled it and checked the filiments, and even swapped in a spare bulb just for good measure.

EDIT: You were right, I found a trailer wiring diagram and both running lights are all on one pin. Damn. So at least its not the truck its the trailer, I can deal with that much easier

Now--- can anybody tell me why the 10A "trailer tow" fuse blew? Is it sized too small, and has anybody had luck replacing with a 15A? I don't want to try without some input but it seems if everybody is blowing it either it and/or the wiring are sized too small?

scr38 · 05-15-2006, 07:54 AM

The 10 amp isn't too small. It blew for the same reason one of your tail lights doesn't work. You have bad wiring to that light.

Toolman61 · 05-15-2006, 05:36 PM

Justin, Just a suggestion: make sureyou check all of your ground connections. Can't tell you how much time I've spent chasing a bad "hot" side problem, only to find an "iffy" ground.

shecycles · 06-16-2006, 08:18 AM

Hi, I'm from the ranks of the electrically inept. However, I did buy a tester and hook up my trailer wiring myself after a 'friend' did the wiring for me by crossing wires and leaving exposed live ends. That was when I was driving an Xterra as my tow vehicle. Everything worked fine for several months after the 'friend' w/the replacement of a few truck fuses and my own wiring. Then out of the blue my trailer tail lights stopped working when I turned the truck's headlights on, though I had blinkers, flashers, and brake lights w/out the headlights. I thought something had gone haywire in the truck since I had the same problem testing w/fresh trailer tail lights and wiring, so went to see the Nissan service dept. about getting it looked at. Of course while I was there finding out the service dept. was too busy to see my X, a slightly used Titan caught my eye and since I'd been wanting a little more tow power anyway...

The new truck didn't answer my trailer lighting problem, though. Again, I have flashers, turn blinkers, and stop lights until I turn the head lights of the truck on. Then the trailer tail lights go dead.

I have the basic two tail lights, a triple red running light on the back plus a triple amber running light on the front of the trailer. The one place I may have flubbed up is on the ground connection for the trailer. I don't understand grounding. The two running lights had a white ground wire on them, so I simply ran the white ground wire from the trailer connector to the two running light ground wires. The front and back running lights work with the truck headlights on. So I'm guessing my tail lights need a solid ground too? They didn't have the white ground wires. Can I just sand down to bare metal at the tongue connection I made to take the ground wire back to the running lights and pop a screw in there? There is no tidy place to screw down the running light grounds. Is it ok to just keep the connector ground wire running back to them?

The dealership tossed in a tow package so I'd buy the truck. It wasn't factory installed. The two relays are in place, but I haven't checked the 10 amp blade fuse yet.

I'm sure this sounds terribly confusing, but it looks pretty durned tidy.

If anyone could point me to a "trailer light grounding for dummies" page or can sort out what I'm saying enough to offer any suggestions, either or both would be welcome!

Robin

shecycles · 06-16-2006, 06:39 PM

Nebbermind, it was a grounding issue and I managed to fix it today. The ground wires didn't want to be run continuously w/connectors and demanded to be screwed down at the tongue. Odd since the lights did work just fine w/the connectors for several months, but as long as there was a solution...

**HudsonValleyTitan** · 06-17-2006, 08:01 AM

Don't forgrt, depending on the year truck you have, there is a recall on the trailer wiring harness.

ryanwickwire · 06-22-2006, 04:58 PM

There is a recall on the wiring harness? Is that for '05's ?

Toxman · 06-22-2006, 06:23 PM

Quote:

Originally Posted by ryanwickwire

There is a recall on the wiring harness? Is that for '05's ?

Yes but it's voluntary. See below.

http://www.nissanhelp.com/Ownership/.../NTB05-086.htm