Passenger light is DIM on both trailers...why?!

[saltymike]

I just put new LED lights on the boat trailer this year, they've been great up until now. I also put new lights on my utility trailer a few months ago. Everything is working fine on both trailers except for the fact that the passenger side light is dim on both of them and I don't know how to trouble shoot it. I've un-wired and re-wired both of them and the problem is still occuring. Thought maybe some water could have gotten in the light but the fact that this is happening with my utility trailer that has never been in water before raises the question....whats going on here? Anyone had this happen? Whats the best way to troubleshoot?

 

[Knightgang]

Re: Passenger light is DIM on both trailers...why?!

Check the ground on that light on bost trailers. Is this the passenger brake light or the running light. You might check the voltage output at your tow vehicle pigtail to ensure it is equal right side to left side...

 

[NYBo]

Re: Passenger light is DIM on both trailers...why?!

Since it is occurring on both trailers, double-check the wiring on the tow vehicle. It sounds like you have something messed up so that the left side trailer lights are finding ground through the turn signal filament.

 

[Paul Ryan]

Re: Passenger light is DIM on both trailers...why?!

Since it is occurring on both trailers, double-check the wiring on the tow vehicle.

Agreed. With the same thing on Both trailers, I would look at the tow rig connection.

When you turn the Flashers on are both lights the same brightness? Or is it only the running lights?

 

[eli_lilly]

Re: Passenger light is DIM on both trailers...why?!

I fought a trailer lighting problem earlier this year and almost pulled all of my hair out before discovering that my lightning controller in the tow vehicle had gone bad. In the end, I used a car battery with a stub trailer connector to manually light each set of the trailer lights. When they all worked, I was like wtf and then realized the controller in the Jeep must've fried. Got a new one and that fixed everything. This was, of course, after rewiring the trailer 20 times in an attempt to find what the problem was.

-E

 

[Paul Ryan]

Re: Passenger light is DIM on both trailers...why?!

I fought a trailer lighting problem earlier this year and almost pulled all of my hair out before discovering that my lightning controller in the tow vehicle had gone bad. In the end, I used a car battery with a stub trailer connector to manually light each set of the trailer lights. When they all worked, I was like wtf and then realized the controller in the Jeep must've fried. Got a new one and that fixed everything. This was, of course, after rewiring the trailer 20 times in an attempt to find what the problem was.

-E

20 times...lmao...Yeah saltymike, I wouldnt rewire the trailers anymore. Like eli_lilly I'm thinking you might have a controller going out. That is if you have one or not. What is your tow rig???? model/make/year

 

[saltymike]

Re: Passenger light is DIM on both trailers...why?!

When you turn the Flashers on are both lights the same brightness? Or is it only the running lights?

Both lights are never the same brightness unfortunately.
I am going to hook it up and work on it tomorrow since i'll have the day off. I'll check the grounds again and then look into the controller, is there a way to tell if it has gone south?

20 times...lmao...Yeah saltymike, I wouldnt rewire the trailers anymore. Like eli_lilly I'm thinking you might have a controller going out. That is if you have one or not. What is your tow rig???? model/make/year

Tow vehicle is a 2001 Tacoma Pre-runner, 3.4L V-6. Boat is 16' bass boat single axle trailer(boat and trailer are 20 years old). I had a feeling it was the tow vehicle's wiring that was the problem but was not sure how to check that.

 

[Paul Ryan]

Re: Passenger light is DIM on both trailers...why?!

Both lights are never the same brightness unfortunately.

Don't worry we'll do the best we can to help you through this. And 9 out of 10times it's really something simple.

Because I don't know, do you have a test light or a multimeter? And do you know how to use them? Just asking cause I don't know.

Second, Are the truck brake lights working correctly? (running/parking, trun, brake, hazard) Check them all...

Thrid, Look up under the truck at the tralier connetor harness...Did someone cut into the truck warness and then tape everything back up? or Has a "plug n play" trailer harness been used? (plug n play= plugs into factory harness.)

I have tommarow off also. (well i have ever day off and have been for nine months now but thats off subject) I'll keep a eye on the thread.

 

[saltymike]

Re: Passenger light is DIM on both trailers...why?!

Don't worry we'll do the best we can to help you through this. And 9 out of 10times it's really something simple.

Because I don't know, do you have a test light or a multimeter? And do you know how to use them? Just asking cause I don't know.

Second, Are the truck brake lights working correctly? (running/parking, trun, brake, hazard) Check them all...

Thrid, Look up under the truck at the tralier connetor harness...Did someone cut into the truck warness and then tape everything back up? or Has a "plug n play" trailer harness been used? (plug n play= plugs into factory harness.)

I have tommarow off also. (well i have ever day off and have been for nine months now but thats off subject) I'll keep a eye on the thread.

Well I do not have a test light or multimeter, been meaning to get one for a long time now. All of the lights on the truck are working fine and the connection looks good underneath, there are no lose wires or sloppy tape jobs. It looks like it was joined onto the trucks harness(could be problem there I suppose). I only took a quick glance as I was out to get the newspaper and still on my first cup of coffee. I guess that should be the first place to check huh? Thanks for your help by the way!

 

[NYBo]

Re: Passenger light is DIM on both trailers...why?!

Your vehicle has separate brake lights and turn signals, so unless your trailers have the same setup, there is a converter somewhere in the wiring harness in the Toyota. The fault may be there.

 

[Paul Ryan]

Re: Passenger light is DIM on both trailers...why?!

Your vehicle has separate brake lights and turn signals, so unless your trailers have the same setup, there is a converter somewhere in the wiring harness in the Toyota. The fault may be there.

K...Good info NYBo...So hook a trailer up.

Is the brake light dim?

Is the turn light dim?

Is the running light dim?

This well help us tell which circuit the fault is in.
The fact the tralier harness is plug in play is good, but also bad. Means that we probably wont find a fault there, but will tell us to move down the line. Which is fine. Unhook the connetor that plugs into the truck harness. Look for dirt, water, blue or white powder. Also look really close at both plugs. Are the terminals (pins) all the same height? Everthing needs to look equal. If the connectors are clean then put them back together and make sure they Lock.