Trailer running lights but no trailer brake or turn signals - seeking advice

[Buh-Bye]

Your three topics have been merged into one. GA_B, Moderator

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Hello all,


As you may have guessed, I'm having some problems with getting brake and turn signal lighting on my trailer. I actually think the problem is on the truck side as I was able to get my neighbor to plug his vehicle into the trailer and everything worked fine. I have already checked and cleaned the grounds but wondering if I just don't have a good ground on the truck side or if there is possibly a short on the wiring harness hooked up to my truck. I didn't notice any visible damage but that doens't mean I just didn't miss it. Another thought was to cehck the fuses but if my truck brake and turn signals are working then I wouldn't think that is the problem but I'm not an electrical person and this stuff is foreign to me. Before I go buy a new harness / adapter, wanted to see if anyone else had some advise or suggestions for me to try. FYI - it is a four prong harness with green and yellow wires for turn / brake, brown for running lights (I believe) and white for ground.​

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Thanks in advance!​

 

[59 starcraft]

Check your fuses. There are separate fuses that power the left and rt turn signal and brake lights. I just went through this with my trailers. Month sure what kind of truck but if it's a ford you most likely have two fuse panels, one inside the car and the other under the hood. Good luck and let's us know what it was..

 

[RichRab]

Need a test light

 

[sonofaskipper]

clean the contacts on the truck side and yes it sounds like a ground issue on the truck

 

[Buh-Bye]

Disregard, not sure why it posted multiple times and not sure how to delete a duplicate thread.

 

[SDSeville]

I would start with testing the connections on your truck with a multimeter or one of those plug-in testers from the car parts store.

 

[southkogs]

I just had to work on mine recently: take a look through this topic and see if any of this helps out - http://forums.iboats.com/forum/gene...wing/8013452-chasing-a-trailer-wiring-gremlin

 

[59 starcraft]

Brake and turn signal are separate from running lights. If running lights are working but nothing else it's most likely a fuse unless someone has just wired or retired the trailer. Don't waste time with test lights until you check the fuses. There should be three or 4 fuses that power the lights on the trailer. Look in your truck owners manual for the fuse panel diagram and you will most likely be set......

 

[Buh-Bye]

So, I have a 2007 Honda Ridgeline RTL. I looked in the truck manual and actually have three fuse boxes. Two under the hood and one under the driver side. I didn't check every single individual fuse but checked the ones related to turn signals and break lights and several others just in case I misinterpreted what the manual said the fuse was for (as I'm not familiar with every abbreviation in there). None of the ones I checked were blown. I also cleaned the connections on the truck side but with no success on either.

I have noticed if I put my hazards on, I'll get one tail light blinking but it is inconsistent and sometimes stops for a second and then picks back up. Also, the brake lights will come on a first time but after I let go and hit the brakes again I get nothing.

Just to throw a general question out there but has anyone ever had their wire harness go bad? Mine plugs into the existing wiring of my truck...meaning it attaches betw/ the truck wiring and the light housing on my Ridgeline with the yellow/brown and green/brown (as well as ground) coming down to the trailer (believe they are called T-harness or something similar buy I could be wrong). Looks like it may have a fuse built into the connectors but I can't pull it apart to check as it doesn't look like it comes apart.

 

[59 starcraft]

No Title

You checked the fuses in this box?

 

[59 starcraft]

http://www.ridgelineownersclub.com/forums/showthread.php?t=15235 Check this link, maybe it will help. Where in SC do you live?

 

[Buh-Bye]

http://www.ridgelineownersclub.com/f...ad.php?t=15235 Check this link, maybe it will help. Where in SC do you live?

Thanks, 59 Starcraft - I now have brake lights but still not getting turn signals. I checked that fuse box in the link you referenced and dont have any fuses in several of those slots which seems odd to me. I checked the manual and its things like "small lights (if equipped)" with the if equipped for several of them. I will run down the road and get some more fuses for the remaining slots and see if that fixes my problem.

I'm in Fort Mill, SC...just outside Charlotte. Been spending a lot of time around Charleston lately though.

 

[Silvertip]

You are wasting time installing fuses for items that are not on the truck. It says "if installed" for a reason. No fuses in that position means your truck does not have the option. If you suddenly have a almost working running light blinking then there is a ground or harness issue on your truck. Check and clean that trailer harness. Yes they can go bad since they are open to the elements and connections (plugs and receptacles) can become corroded.

 

[NYBo]

Your truck uses separate bulbs for the brake and turn signal lights so there has to be an adapter somewhere to convert to the standard four wire trailer hookup. It's probably part of the harness. My guess is that the adapter has gone bad.

 

[Fleetwin]

I have noticed if I put my hazards on, I'll get one tail light blinking but it is inconsistent and sometimes stops for a second and then picks back up. Also, the brake lights will come on a first time but after I let go and hit the brakes again I get nothing.
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That is a classic example of a bad ground. You say your trailer works fine behind another vehicle-correct?

Your vehicle plug has a white wire. That is the ground. Where does it go?

In the meantime, you can just overlay it with another wire, attached to a known good ground, and test it.

 

[bruceb58]

Your truck uses separate bulbs for the brake and turn signal lights so there has to be an adapter somewhere to convert to the standard four wire trailer hookup. It's probably part of the harness. My guess is that the adapter has gone bad.

++++1

 

[Buh-Bye]

Your truck uses separate bulbs for the brake and turn signal lights so there has to be an adapter somewhere to convert to the standard four wire trailer hookup. It's probably part of the harness. My guess is that the adapter has gone bad.

You are right in that there are separate bulbs for the brake and turn lights. I believe you are also correct in the adapter being part of the wire harness. I ordered a new harness that should get here this week and will test that out.

 

[Buh-Bye]

That is a classic example of a bad ground. You say your trailer works fine behind another vehicle-correct?

Your vehicle plug has a white wire. That is the ground. Where does it go?

In the meantime, you can just overlay it with another wire, attached to a known good ground, and test it.

Thanks for the input, Fleetwin. I checked the ground on the truck and believe it is a good grount but I have not tried an overlay but can test that option as well. I hesitate to think my ground isn't good on the basis that it had worked fine in the past (doesn't mean it still does by any means). I already ordered a new adapter as I was worried about the converter going bad like NYBo talks about. I'll post any updates after I try those options. Thanks!

 

[Fleetwin]

Thanks for the input, Fleetwin. I checked the ground on the truck and believe it is a good grount but I have not tried an overlay but can test that option as well. I hesitate to think my ground isn't good on the basis that it had worked fine in the past (doesn't mean it still does by any means). I already ordered a new adapter as I was worried about the converter going bad like NYBo talks about. I'll post any updates after I try those options. Thanks!

I'm not discounting the convertor. But, I do the CHEAP stuff first>

 

[Buh-Bye]

Well....looks like it was a bad harness and converter. $60 for a new one and everything is running as it should be. Thanks everyone for the advice and input. Appreciate it.