DIAGRAM FOR: The Proper Way To Wire Trailer Lights?

zbishka

Cadet
Joined
Aug 24, 2009
Messages
22
I bought and had installed a new set of trailer lights for my boat trailer.
As long as I ran no lights on my vehicle the trailer lights work great.

When I turned on my lights (Head and/or Running) on my vehicle, no matter which t/s I use ALL the lights on the trailer blink like hazard lights even the running/marker lights on the trailer. So in an attempt to rewire all the trailer lights to the wiring harness hooked up to my vehicle I'd like to follw a diagram as I am clueless as to how to do this and cause obviously the people who did it don't know what they are doing either.I do believe it goes beyond a ground problem. Not to mention that the first time I launched the boat and put the trailer into the water ALL the trailer lights blew. Why would anybody put Non Submersible and/or Non Waterproof trailer lights on a boat trailer? Is there a reasonable explaination for this? Any help I can get would be greatly appreciated. Thanks All.
 

KD4UPL

Senior Chief Petty Officer
Joined
Feb 13, 2010
Messages
653
Re: DIAGRAM FOR: The Proper Way To Wire Trailer Lights?

Your problem sounds exactly like a bad ground to the trailer. Do the turn signals work properly with the marker lights off? If so I'm even more sure it's a bad ground on the trailer.
 

tominohio

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Joined
Apr 22, 2011
Messages
7
Re: DIAGRAM FOR: The Proper Way To Wire Trailer Lights?

I just installed a cheap trailer light set (Harbor Frieght) on a boat trailer I converted into a utility trailer. I went to check the turn signals, and they both blink on the trailer with either one I turn on in the truck. Running lights don't work at all. Took the grinder to the metal where the ground wire is connected, no change. Thoughts????

Diagram???
 

canoe/kayak

Recruit
Joined
Jul 24, 2011
Messages
4
Re: DIAGRAM FOR: The Proper Way To Wire Trailer Lights?

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Grandad

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Jun 7, 2011
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Re: DIAGRAM FOR: The Proper Way To Wire Trailer Lights?

Not to mention that the first time I launched the boat and put the trailer into the water ALL the trailer lights blew. Why would anybody put Non Submersible and/or Non Waterproof trailer lights on a boat trailer? Is there a reasonable explaination for this?

The explanation for the blown bulbs is an age old problem with boat trailers. As you back down the launch ramp with your foot on the brakes, the bulbs get quite hot. This is normal. Then you dump them in cold water. This is not normal. Traditionally boaters have always disconnected the trailer plug before launching so that the lamps are not hot when they hit the water.
It's expensive to manufacture submersible lights. I've found the answer to be using LED tailights. At first, I was concerned about submersing them as well. My LED assemblies seem to be heavily clear epoxy coated, though the manufacturer made no claim that they are submersible. At the very least, I know they don't get hot, so there's no shock when they hit cold water. And by the way, don't even try to seal the tailights; they'll get water in them somehow and then they'll never drain. I just make sure there's good drain holes in mine so they drain again quickly. - Grandad
 

Bob's Garage

Chief Petty Officer
Joined
Apr 10, 2008
Messages
590
Re: DIAGRAM FOR: The Proper Way To Wire Trailer Lights?

I bought and had installed a new set of trailer lights for my boat trailer.
As long as I ran no lights on my vehicle the trailer lights work great.

When I turned on my lights (Head and/or Running) on my vehicle, no matter which t/s I use ALL the lights on the trailer blink like hazard lights even the running/marker lights on the trailer. So in an attempt to rewire all the trailer lights to the wiring harness hooked up to my vehicle I'd like to follw a diagram as I am clueless as to how to do this and cause obviously the people who did it don't know what they are doing either.I do believe it goes beyond a ground problem. Not to mention that the first time I launched the boat and put the trailer into the water ALL the trailer lights blew. Why would anybody put Non Submersible and/or Non Waterproof trailer lights on a boat trailer? Is there a reasonable explaination for this? Any help I can get would be greatly appreciated. Thanks All.

I just installed a cheap trailer light set (Harbor Frieght) on a boat trailer I converted into a utility trailer. I went to check the turn signals, and they both blink on the trailer with either one I turn on in the truck. Running lights don't work at all. Took the grinder to the metal where the ground wire is connected, no change. Thoughts????

Diagram???

Neither one of you have mentioned the type tow vehicle you have. If it is the type vehicle with separate stop/turn signals then you must have a control devise to split the current flow to the trailer.

Also, if you mean the fuses all blew, the people doing the work may have used the press on type wire connector to make the connections and they are not waterproof. The new trailer lights, at least the good ones, are submersible and the bulbs do not come in contact with the water. I think this is due in large part to trailers having disc brakes and must now remain electrically connected to the tow vehicle to back up. At least without the bother of blocking the actuator every time.
 

Grandad

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Joined
Jun 7, 2011
Messages
1,504
Re: DIAGRAM FOR: The Proper Way To Wire Trailer Lights?

Also, if you mean the fuses all blew, the people doing the work may have used the press on type wire connector to make the connections and they are not waterproof.
Hi Bob, 12 volts can't short enough current through water to blow fuses, so I'm assuming the glass on the bulbs cracked allowing air into them. The filaments will then burn up within seconds. Been there, done that, (more than once). Learned to carry lots of spares for those times I forgot to unplug. Now with my LEDs, I can leave the plug connected and still have my electric brakes while on the ramp (until they get wet). - Grandad
 

canoe/kayak

Recruit
Joined
Jul 24, 2011
Messages
4
Re: DIAGRAM FOR: The Proper Way To Wire Trailer Lights?

a bare wire touching the trailer frame somewhere will blow fuses everytime you turn on the lights. Check your wires carefully if fuses are blowing as soon as you turn lights on or step on brakes
 

tominohio

Cadet
Joined
Apr 22, 2011
Messages
7
Re: DIAGRAM FOR: The Proper Way To Wire Trailer Lights?

I have a 2001 Ford F150. According to the other cheap thing I got at harbor frieght (plugs into the tow vehicle) the signals are being sent to the plug correctly.
 

Jetwash

Seaman Apprentice
Joined
Jul 12, 2011
Messages
49
Re: DIAGRAM FOR: The Proper Way To Wire Trailer Lights?

I bought and had installed a new set of trailer lights for my boat trailer.
As long as I ran no lights on my vehicle the trailer lights work great.

When I turned on my lights (Head and/or Running) on my vehicle, no matter which t/s I use ALL the lights on the trailer blink like hazard lights even the running/marker lights on the trailer. So in an attempt to rewire all the trailer lights to the wiring harness hooked up to my vehicle I'd like to follw a diagram as I am clueless as to how to do this and cause obviously the people who did it don't know what they are doing either.I do believe it goes beyond a ground problem. Not to mention that the first time I launched the boat and put the trailer into the water ALL the trailer lights blew. Why would anybody put Non Submersible and/or Non Waterproof trailer lights on a boat trailer? Is there a reasonable explaination for this? Any help I can get would be greatly appreciated. Thanks All.

If some lights are working then most likely the ground connection is fine. I would check the color codes on the trailer side to see if they line up with the vehicle plug. You can always run a single raw wire to both plugs or double ended gator clips. Youll need to be hooked to the boat trailer and put another connection between the ground wire on both plugs (white if memory serves.) Don't use a test light for the connection. You won't get an accurate reading.

I have a hunch the running lights wire is merged with the blinker wire. May not be AT the plug. If you must disconnect the wires from the trailer plug and check those independently of the plug.
 
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