Trailer lights work......sorta

[kfa4303]

Hi all. I'm having a bit of an issue with my trailer lights. they only work when i have my headlights on, and then they just stay on constantly. I installed them about 6 months ago and they used to have complete functionality and would respond correctly to braking, turn signals, reverse and head lights, etc..... all of the lights on my truck still work fine, and I took extra care to safely tuck away all of the wires on the trailer. I also ran an independent ground wire to each light as well to prevent shooting out when submerged. the lights themselves are high and dry on PVC guide posts and have never been submerged. I'm thinking I may have a short in the adapter coming off of my tail lights that plugs into the trailer's set of wires, but I'm not sure. is there any way I can test the various components to track down the problem? I'm not very good with electrical stuff (obviously), but I'm willing to learn and give it a try. thanks!

 

[Bob_VT]

Re: Trailer lights work......sorta

who or how is the harness wired on the truck side? What kind of truck? If it is foreign the adapter might be toast.

I would start with a mutimeter and test the truck side of the harness.

 

[kfa4303]

Re: Trailer lights work......sorta

HI Bob. It's a good 'ol '95 Ford Ranger pickup truck, so it's nothing fancy. I did have to tap into the tail light wires to install the adapter that plugs into the trailer, and I think that may be the problem. I'm guessing that one, or more, of my connections is bad. I'm not sure how to use a multimeter to test it though. Am I correct it thinking that because they do light up when I turn the headlights on, that the wires in the trailer are ok, or could I have a problem on that end too? these are the lights I'm using. Thanks.

http://www.iboats.com/Submersible-T...43560574--**********.278517193--view_id.49294

 

[Yacht Dr.]

Re: Trailer lights work......sorta

When you say that you ran independent grounds to each light .. what do you mean by that ? to the trailer or the lights to the ground on the vehicle..

Most lighting issues come from a bad ground from my experience ..

Good ground wire from the trailer to the vehicle is key to diagnosing the problem IMO.

I Use a direct Independant ground wire for my trailer to truck ( aside from the normal connectors ). Nothing can break the circuit unless you have crappy wires on the lead end of the connection or bulbs ..

Use the Resistance setting on the meter to show if you have high resistance on one or another connection in your wiring.

YD.

 

[lckstckn2smknbrls]

Re: Trailer lights work......sorta

Hook your trailer in to a different tow vehicle that will tell you if the trailer is ok. Then do the same to your truck with a different trailer.

 

[ac0j]

Re: Trailer lights work......sorta

Does this Ranger have yellow turn signals and seperate brake lights in back? If so you would have to have an adapter to make trailer lights work correctly. If they were previously working on this truck, then the adapter box in the truck may be bad. I have never run into a trailer plug that provided reverse lights!?!

 

[kfa4303]

Re: Trailer lights work......sorta

Hi all. As far as the grounds go, I added a white, ground wire from each light and connected them to the white ground wire on the trailer side plug per some suggestions I read here in the forums. I tapped into the lights of the truck according to the instructions on the trailer kit using the crimp on connectors. I do have separate, yellow turn signals and regular, red break lights on the truck itself. when I first hooked it all up it worked great for my first couple trips, but lately I can only get the trailer lights to come on when I have the headlights on. it's better than nothing, but the trailer lights don't function as blinkers or proper break lights anymore which is not so ok. I thought about hooking my truck/trailer up to a different vehicle to test them, but I can't think of any one I know with a trailer :/ if I were to use a multimeter, what would I want to look for? any thoughts as to why the trailer lights work when headlights are on, but not in any other mode? does that mean that the wire(s) that comes off of my truck's blinkers and break lights are bad, but while the ones coming off of the headlights is ok? thanks again for any help.

 

[Bondo]

Re: Trailer lights work......sorta

Hi all. As far as the grounds go, I added a white, ground wire from each light and connected them to the white ground wire on the trailer side plug per some suggestions I read here in the forums. I tapped into the lights of the truck according to the instructions on the trailer kit using the crimp on connectors. I do have separate, yellow turn signals and regular, red break lights on the truck itself. when I first hooked it all up it worked great for my first couple trips, but lately I can only get the trailer lights to come on when I have the headlights on. it's better than nothing, but the trailer lights don't function as blinkers or proper break lights anymore which is not so ok. I thought about hooking my truck/trailer up to a different vehicle to test them, but I can't think of any one I know with a trailer :/ if I were to use a multimeter, what would I want to look for? any thoughts as to why the trailer lights work when headlights are on, but not in any other mode? does that mean that the wire(s) that comes off of my truck's blinkers and break lights are bad, but while the ones coming off of the headlights is ok? thanks again for any help.

Ayuh,... Yer lookin' for 12V on which ever circuit yer checkin'....

 

[kfa4303]

Re: Trailer lights work......sorta

ok. so would I stick the "probe" of the multimeter into each of the female connections on the truck-side trailer plug? do i need to turn the blinkers on to test for the 12V signal, or is it constant when the truck is running? thanks again.

 

[Bondo]

Re: Trailer lights work......sorta

ok. so would I stick the "probe" of the multimeter into each of the female connections on the truck-side trailer plug? do i need to turn the blinkers on to test for the 12V signal, or is it constant when the truck is running? thanks again.

Ayuh,... 1 probe to the circuit yer testing, 'n the other probe to ground....

Ya, if ya don't turn on a light, there ain't gonna be any power....

 

[hungupthespikes]

Re: Trailer lights work......sorta

OP "I tapped into the lights of the truck according to the instructions on the trailer kit using the crimp on connectors"
First place to look. Crimp connectors are poor at best.
huts

 

[cribber]

Re: Trailer lights work......sorta

If you used an aftermarket wiring harness that has a controller box that may be your culprit. I blew mine by hooking my four pin connector on my tow vehicle through and adapter to a seven pin trailer connection. The electric surge brakes killed the controller and I only had taillights and nothing else worked.

 

[5150abf]

Re: Trailer lights work......sorta

Get a battery charger or battery and run a wire to each lead one at a time on the trailer, if all the lights work then you know it is the truck.

I have a 99 ranger and have had some probelms with the lights, mine has the tow package and seperate wire harness for the trailer though and the probelms have almost always been fuses or a bad ground.

I just went round with a fuse that looked good but wasn't, wires all checked out and I had checked the fuses several times before I took a know good fuse and just started replacing them till I found it.

All you need to check the truck side is anything 12 really, I use an ignition buzzer so I don't have to try and handle a meter or test light and it works pretty well.

To test you need to put the negative lead on the ground then turn on the turn signals, brake lights and running lights one at a time and make sure you have power at the plug, and no with the truck just running and no lights on there won't be any power to the plug.

 

[kfa4303]

Re: Trailer lights work......sorta

Hello again everybody. Sorry I sort of left this thread hanging. Here's an update. I replaced the break light bulb on my truck and now all lights on my truck work perfectly, just as they should. However, I can still only get the lights on the trailer to function when I turn my headlights on. As a result, I know that both bulbs in each set of trailer lights work, at least in headlight-indicator mode.
Here's where I need some conceptual clarification. Is it correct to assume the the trailer lights are properly grounded because they do work, if only in headlight mode? If they were not properly grounded, then they shouldn't come on at all, in any mode, right? If that is correct, where should I look next? As I said the lights on my truck work perfectly, so that makes me think that all of the wires/fuses on the truck side are ok. Could the lack of function in turn signal and/or break mode in the trailer be due to a bad fuse even though the truck lights work fine? I don't have any other fuses aside from the ones in the truck.
I looked over all of the connections and there are no obvious signs of damage or scorching etc.......It all worked when i first hooked it up, so I hope that means I can get it all to work again. Thanks again for any help.

P.S.
here is the current wiring diagram of my trailer.
I'm assuming the brown wires are working because I do have function in headlight mode? I guess that means that the green and yellow wires are not functioning?

 

[GA_Boater]

Re: Trailer lights work......sorta

You keep saying everything works when you turn on the headlights. Are you saying that you have running (tail) lights and brake lights or are you saying only the tail lights work? Spend 3 bucks here http://www.iboats.com/Seasense-EZ-T...21153783--**********.312929027--view_id.56357 and make sure the truck wiring is working.

Next question - Did the truck have a towing package? If no, did the kit have a convertor for connecting a yellow turn signal to a common bulb (tail/brake two filament bulb) trailer? Something like these http://www.autozone.com/autozone/pa.../N-8ijmg?counter=5&itemIdentifier=853062_0_0_ I think you need a convertor.

 

[kfa4303]

Re: Trailer lights work......sorta

Sorry for the confusion. The trailer lights only work when I turn on my headlights, but they do not brighten when the brakes are applied, nor do they function as blinkers while in this mode. If I turn the headlights off and try the brake or blinkers, I get no response. My truck did not have a trailer package, so I had to get a converter/adapter per your description. However, it is a sealed, flat, oval shaped unit with no apparent fuse? It looks sort like this:




I like the little tester you showed I think I may go get one now and see if I can determine which wires are working properly. Was my previous assumption, that the trailer lights are at least properly grounded as evidenced by there ability to function in headlight mode, correct, or could there still be a grounding issue as well?

Electrical is not my cup of tea, but I want to learn more.



Many thanks.

 

[kfa4303]

Re: Trailer lights work......sorta

Update......so I went and got a little plug in tester per Ga boaters suggestion (great little gizmo btw) and it says that all of the truck side wiring (taillight, RT, LT) is good to go. So I guess that means that my problem is on the trailer side of things. I double checked all of the connections again and they seem fine. I think it may be some sort of grounding issue, but I'm not sure where. When I first installed the wiring kit I ran an additional, white, ground wire from each set of lights and tied them into the white ground wire on the plug per a suggestion I have read here in the forums. Each additional ground wire is securely connected to one of the mounting posts on the backside of the trailer lights using a crimp on eye adapter. When these additional ground wires are disconnected all trailer light function is stopped, even in headlight mode. However, once I reconnected the white ground wires to the common, white ground wire on the plug, headlight mode function was restored, but still not brake and/or turn signal function :/
Do I need to run another white, ground wire off of the other mounting post on the backside of each set of trailer lights and tie them into the white ground wire as well, so that I can get full functionality? I don't know why they would work in headlight mode, but not break light/ turn signal mode, but running an additional ground is all I can think of :/ Thanks again for any help.

 

[kfa4303]

Re: Trailer lights work......sorta

Here's a diagram of how I have my trailer wired with the additional ground wires. however, none of my ground wires are mounted to the trailer itself. instead they are all joined together with a wire nut to form a common ground. could this be the problem? If so, should I add an eye to each of the three ground wires and then mount them to the trailer with a self tapping screw of some sort? Thanks again.

 

[GA_Boater]

Re: Trailer lights work......sorta

Do the three red marker lights at the back work when the truck headlights are on?

 

[kfa4303]

Re: Trailer lights work......sorta

I don't have the three marker lights across the back as seen in the diagram. sorry, that was just a stock diagram i got off the web and modified. still stumped as to why the lights would only work when the headlights are on, but not when I hit the brakes and/or turn signals :/ I'm assuming that the trailer lights are properly grounded because they do work (at least when the headlights are on), but that doesn't explain why they don't work in any other mode. thanks again for any ideas.