quick question

eaw1952

Cadet
Joined
Sep 8, 2003
Messages
22
I've got a problem with this new trailer, all the lights work great---until--- I put the headlights on.<br /><br />when the headlights are on the trailer lights go out, all of them when the brake is pressed.<br /><br /> turn signals make the whole thing blink both sides and marker lights all blink with the turn signal, but only with the headlights on.<br /><br />It's on a 1994 F-150 but all I did was buy the wiring 'T' splice and plugged it in, so I'm saying that the truck isn't it. maybe. unless the flasher unit has something to do with it, it is NOT the heavy duty one.<br /><br />For a ground I ground a spot clean on the frame and bolted the white ground wire to that.<br /><br />why does the headlights being on screw it up?<br /><br />thanks!
 

BrianFD

Senior Chief Petty Officer
Joined
Jul 30, 2003
Messages
748
Re: quick question

I'm thinking you have a wiring problem on the trailer, probably the ground. Back-feeding the lights from one side to the other would make it appear that all the lights are blinking. Is one side (the side you've lit the signals on) a little brighter than the other? Try running a separate ground wire from the tow vehicle (externally at first) to each light one at a time, after isolating the ground on the light from the trailer wiring. Also, double check (with a 12v meter or light) that you've got the polarity correct between the vehicle & the trailer. I also think the headlights causing all the lights to go out is related.<br />Good luck & let us know your progress.<br />Brian
 

eaw1952

Cadet
Joined
Sep 8, 2003
Messages
22
Re: quick question

the trailer ground is plugged into the ground on the truck frame, it works with the other trailers so I'm thinking it's ok.<br /><br />I still don't understand why the lights function properly when the headlights are off, actually they work fine with them on until I hit the brakes.<br /><br />I'll end up rewiring this factory wired trailer, I can see it now! :mad:
 

lakeman1999

Chief Petty Officer
Joined
Apr 20, 2003
Messages
550
Re: quick question

There is a possibility that you do not have an adequate ground to work all of the lights, and so when the light blinking is off (between blinks), it furnishes a better ground for the other lights. on the main ground wire from the towing vehicle, make sure that the connection (plug) is making good contact, and make all ground connections to frame (of towing vehicle, and trailer) a boltet through (and preferably a bored and tapped hole). Another thing to be wary of, if you wrap a ground wire around the shank of a screw (even with a washer), when you tighten down on the wire, the screw head/washer will often clamp, and cut the ground wire, giving you a weak ground, that you do not notice. It is best to drill and tap a hole in frame, crimp an eyelt on the end of the ground wire, put screw through it, and screw into tapped hole in trailer/vehicle frame, "VIOLA" problem is corrected. :D :D :D :D :D :D :D :D
 

Northern Eclipse

Senior Chief Petty Officer
Joined
Jun 24, 2003
Messages
665
Re: quick question

look at the brown wire over the entire trailer pay close attention at points were the wire contacts the trailer and see if you find any splices or splits on the insulation allowing bare wire to contact the trailer this will ground out the wire on the trailer frame, if no damage to wire then do the same for yellow an green..a small short does not always blow the fuse..but can cause light malfunctions.
 

eaw1952

Cadet
Joined
Sep 8, 2003
Messages
22
Re: quick question

ok, here's where we are.<br />there's no way to walk the wires they run through the trailer. <br /><br />question: If there is a short wouldn't you notice it other than just when the headlights are on? the lights work great as long as the headlights are off.<br /><br />that sound like a ground problem to you guys?<br /><br />the ground is a drilled hole through frame. What would be better?
 

lakeman1999

Chief Petty Officer
Joined
Apr 20, 2003
Messages
550
Re: quick question

You not only have to check the ground to trailer (white wire), you also need to check each lights grounding too trailer. Are you depending on the ball to ground to vehicle?<br /> :D :D
 

eaw1952

Cadet
Joined
Sep 8, 2003
Messages
22
Re: quick question

no. it's grounded to the frame.<br /><br />I still don't understand how a bad ground would only effect the lights when the headlights are on, and the lights work fine otherwise. <br /><br />explain it to me like I'm 5, I may yet get it.
 

lakeman1999

Chief Petty Officer
Joined
Apr 20, 2003
Messages
550
Re: quick question

A bad ground could possibly only effect the other lights when the headlights are on because your ground could be weak, only allowing a portion of the currant for total lights to pass, with headlights off, you may have enough grounding capacity to handle but turn on the headlights (which uses a lot of power) ground could possibly not be good enough to handle them, and other lights simultanously. I am just saying that this could be a possibility. I am not an electrical engeneer, but I am very knowledgable on wireing for everyday use. I also know, that sometimes rules of the road (rules of electronics) sometimes get sidetracted, and it is a problem finding fault, and curing the problem. In my lifetime, I have cured many problems with many items, washers, ranges, dryers, lighting systems and so on. Upon making them whole again, I am asked what I did to fix it, and my answer is I do not know. This usually pisses the qusteioner off, and I explain that I just went into the system, did many things, and now it works, although I do not know which, or what made it work, and possibly it was a littlee of all that fixed it. Where as today many service men are parts changers, they keep putting on new parts (charging you for all of them even if it is not the problem), till they correct the problem. In some instances they will never find the problem, because there is no clearcut solution, or bad part. But what the system needs is just a complete going over, tightening this, scraping off corrosion here, and there, replace a frayed wire here, and there, banging this, and tapping that, and "VIOLA" now it works, and how the h*ll should I know what was wrong with it?? Well, let me tell you, in my 70 years on this earth, I have came along behind a lot of experts, and not knowing a danmed thing about it (what ever it was/is) got it to work when they couldn't, because all they did was replaced good parts for new parts, and I tapped this, and twisted that, and something/all I did helped. So, as I sid in my previous post, go over it, and loosen, check, and retighten, and reconnect every light or connection/ground point on the system. :D :D :D :D :D :D :D :D
 

Northern Eclipse

Senior Chief Petty Officer
Joined
Jun 24, 2003
Messages
665
Re: quick question

Eaw1952 you gotta look at the wiring for a break or bare spot, I mention brown becuase that is your running lights, so as long as your headlights are off its not hot, turn lights on it hot if it grounding out lights go off...I'm not a wiring expert but I discoverd this with my own trailer had the same problems you describe, when I found the break in the insulation I could barely see copper, but it was just enough to ground out on the trailer frame, I found the break at the point were the wire exited from the inside on the trailer frame. I to went mental looking for a poor ground at first.
 

PDS

Petty Officer 1st Class
Joined
Aug 15, 2002
Messages
239
Re: quick question

ground each set of lights or even marker lights independently. You'd be surprised what bad grounds can make your brake lights do or turn signal lights do. Relying on one ground from truck frame to trailer just isn't enough. PDS
 
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