Help with lights please!!!

[Quadzilla724]

I'm new to boating and bought a boat and nice trailer. The problem is the lights are all jacked up. Here are the symptoms. I'm hoping you can tell me where I need to start looking, because I have NOOOO idea....

Left Turn Signal = Left Turn Signal
Rt Turn Signal = Right Turn Signal
Running Lights = Running Lights
Brakes = Nothing
Left Turn Signal w/ Brake = Railroad Lights (rt & lt signals alternate)
Right Turn Signal w/ Brake = Railroad Lights (rt & lt signals alternate)
Running Lights w/ Brake = Nothiing
Hazards = Nothing

I'm 99% sure the tow vehicle is fine because I had just pulled my friends trailer the week before with no issue. I checked all the fuses just in case and all were good.

I checked the ground wire on the trailer, cleaned it, reattached it.

I found a flatted part of the wiring near the right light and, cut it out and spliced it.

i cleaned any corrosion I could find on the harnesses.

Nothing changed. Nothing worked

What should I do first?

Tow vehicle is a '03 trailblazer with factory adapter (7-way to 4-way?). Trailer fits into that.

Should I rewire the trailer 4-way first? Not sure of next step or best way to diagnose. I don't have a lot of electronic testing equipment, so if you suggest I use something like that, please let me know the name of it, cost and where I can get one.

Thanks, from a rookie!!!

 

[Boats-A-lots]

Re: Help with lights please!!!

Almost what I was going through last month. We tow our boat with our Hummer H2. It has separate fuses for the tow lights. It kept blowing the 15 amp fuse for the running lights. Finally I put a 30 amp fuse in it and watched for smoke.. didn't take but about 5 secs. What had happened on mine was the marker light bar on the bottom of the trailer that run from port to starboard was grounding out. I cut the wire going to them and taped it up. Replaced the fuse back to a 15 amp and problem solved. I'm rebuilding that light bar with stainless steel parts as I launch in salt water and dont want this to happen again.

This may not be your problem, but check that light bar anyway.

 

[Bob's Garage]

Re: Help with lights please!!!

I'm new to boating and bought a boat and nice trailer. The problem is the lights are all jacked up. Here are the symptoms. I'm hoping you can tell me where I need to start looking, because I have NOOOO idea....

Left Turn Signal = Left Turn Signal
Rt Turn Signal = Right Turn Signal
Running Lights = Running Lights
Brakes = Nothing
Left Turn Signal w/ Brake = Railroad Lights (rt & lt signals alternate)
Right Turn Signal w/ Brake = Railroad Lights (rt & lt signals alternate)
Running Lights w/ Brake = Nothiing
Hazards = Nothing

I'm 99% sure the tow vehicle is fine because I had just pulled my friends trailer the week before with no issue. I checked all the fuses just in case and all were good.

I checked the ground wire on the trailer, cleaned it, reattached it.

I found a flatted part of the wiring near the right light and, cut it out and spliced it.

i cleaned any corrosion I could find on the harnesses.

Nothing changed. Nothing worked

What should I do first?

Tow vehicle is a '03 trailblazer with factory adapter (7-way to 4-way?). Trailer fits into that.

Should I rewire the trailer 4-way first? Not sure of next step or best way to diagnose. I don't have a lot of electronic testing equipment, so if you suggest I use something like that, please let me know the name of it, cost and where I can get one.

Thanks, from a rookie!!!

Get a trailer plug tester. It has led's that will verify vehicle system is working. May not need it now, but it's cheap and useful.

The signal, hazard and brake lights are on the same wire; yellow for the left, green for the right.

The running lights are on the brown wire, split at the plug to run down each side.

White wire is the ground.

You can drive yourself crazy trying to fix someone else's screwed up wiring. My suggestion is to get a new plug with enough wire to reach more than the end of the trailer, and enough white wire to run from the plug to the rear of the trailer X2 plus 12".

I prefer soldering my connections, and splices, coating them with liquid tape, then encase in heatshrink insulator, covering 2" of the splice. Assume all connections and splices are performed in this manner.

Starting at the plug take the white wire, splice 2 additional wires onto it so you now have 3 , one of which is short, 2 that will reach the end of the trailer+. Find an appropriate location to attach the short white wire to the trailer, using a wire lug.

This short wire will be your chassis ground for the marker lights.

Run one white, a green and a brown wire down the right side of the trailer to the light. Make a splice in the brown wire for the side marker, leaving enough wire for future use.

Do the same on the left side with the yellow, brown and white wires.

At the lights cut the lug off the white wire from the light and connect it to the ground you brought from the front. Attach the brown wire to the brown wire from the lights and from the rear marker to the side of your choice. Join the green and yellow wires to the proper wire coming from the lights.

Secure all wires to the trailer using zip ties thru holes if available or in some other manner, do not use metal clips as they can damage the insulation.

By running a separate ground to each light you will have reduced the possible places for problems to occur. Make good connections, and protect them well from water intrusion and you will have no more problems. Remember, water is the enemy of your electrical system.

 

[Gpayne]

Re: Help with lights please!!!

Sounds like you've got a bad ground somewhere. Most trailer taillights ground through the mounting studs. Make sure they're clean and tight. Also, if they mount on brackets, make sure the brackets are mounted tight to the trailer frame. I had the same problem on one of my old trailers and I ended up running jumper wires from the taillight mounting studs directly to the frame and problem solved.

 

[still afloat]

Re: Help with lights please!!!

If your trailer is a tilt model or if the frame rails bolt to the tongue, make sure you have a good ground at the rear of the trailer. Just because the wire is connected don't mean its grounded.
On most tilt trailers or bolt together frames I run a separate ground to the rear or add ground straps to both frame rails from the tongue.

 

[UncleWillie]

Re: Help with lights please!!!

Left Turn Signal w/ Brake = Railroad Lights (rt & lt signals alternate)
Right Turn Signal w/ Brake = Railroad Lights (rt & lt signals alternate)
Running Lights w/ Brake = Nothing
Brakes = Nothing <----<<< Solve this first!
Hazards = Nothing

I'm 99% sure the tow vehicle is fine because I had just pulled my friends trailer the week before with no issue.

If you pulled your friend trailer AFTER the problems started, it might mean something.
BEFORE means nothing!

Hazard lights are the Brake lights flashing together.
Turn signals are the Brake lights flashing independently
All your issues are related to the brake circuit.
The symptoms indicates the problem is in the tow vehicle.
Light Converter Box???

And as usual... When it absolutely makes no sense and appears to be magic, it is a Ground Issue!

 

[Quadzilla724]

Re: Help with lights please!!!

If you pulled your friend trailer AFTER the problems started, it might mean something.
BEFORE means nothing!

Hazard lights are the Brake lights flashing together.
Turn signals are the Brake lights flashing independently
All your issues are related to the brake circuit.
The symptoms indicates the problem is in the tow vehicle.
Light Converter Box???

And as usual... When it absolutely makes no sense and appears to be magic, it is a Ground Issue!

I had my neighbor bring his Jeep down and hook up the trailer and it had the same problem. However, I gave up and went and bought a complete new lighting kit from the 7-to-4 way connector to the taillights. Magically, this had the same problem!!!!! I had the ground connected to the tongue. I removed that, and took a copper wire, attached it to the ground wire (the SAME ground wire connected to the tongue, mind you) and connected the copper wire to the tongue....it worked. (huh?). So looks like the problem is now solved. How? I have not idea. Fortunately, I bought a very inexpensive kit.

Thank you ALL for all your help on this problem. It is greatly appreciated.