Trailer Lights Gurus--Got a Question.

[JWR]

Oh nonsense !! There is obviously no ground problem since at times he has trailer lights. Secondly the trailer lights work just like the truck -- when he has truck lights and/or ignition on.

Conclusion: There is no problem and there was no problem in the first place.

 

[npalen]

Oh nonsense !! There is obviously no ground problem since at times he has trailer lights. Secondly the trailer lights work just like the truck -- when he has truck lights and/or ignition on.

Conclusion: There is no problem and there was no problem in the first place.

The only problem was the guy wiring the new trailer lights if you're referring to me as the OP but that was taken care of with a little help from my friends here at TBN. Remember the lyrics "I get by with a little help from my friends"?

 

[charliecrew]

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smile.amazon.com

Installed these lights on my little utility trailer and everything works correctly except the tow vehicle lights have to be on for any trailer lights to work.

That wasn't the case with the old trailer lights and everything works correctly on the pickup to which the trailer is attached.

I suspect this issue is related to the fact that the '03 Dodge Dakota doesn't have automatic lights, the switch has to be turned on manually.
I can live with this but wondering if there is a way "around it"?

TIA for any comments.

The trailer lights mirror the tow vehicle lights. If this is what ic happing it is nonmail.

 

[JohnInLoudon]

Amazon.com: iBrightstar IP68 Waterproof Square Trailer Lights kit, Red Brake Stop Tail Running License LED Light Lamp for 12V Camper Truck RV Boat Snowmobile Marine Under 80", DOT Compliant: Automotive

Buy iBrightstar IP68 Waterproof Square Trailer Lights kit, Red Brake Stop Tail Running License LED Light Lamp for 12V Camper Truck RV Boat Snowmobile Marine Under 80", DOT Compliant: Tail Light Assemblies - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

smile.amazon.com

Installed these lights on my little utility trailer and everything works correctly except the tow vehicle lights have to be on for any trailer lights to work.

That wasn't the case with the old trailer lights and everything works correctly on the pickup to which the trailer is attached.

I suspect this issue is related to the fact that the '03 Dodge Dakota doesn't have automatic lights, the switch has to be turned on manually.
I can live with this but wondering if there is a way "around it"?

TIA for any comments.

It's a good trouble shooting plan to cut the problem in half by determining whether the truck r the trailer is the problem. This tester will do that Amazon.com: SeaSense EZ TROUBLESHOOTER Circuit Tester: Sports & Outdoors

Just plug it in and cycle through parking and brake lights. The LEDs will tell you where you have power.
A multimeter can also work if you have one, or this ( Premium LED Bulb Automotive Circuit Tester, 6-24V Test Light with 135 Inch PU Extended Spring Wire, Sharp Hard Steel Probe Vehicle Circuits Low DC Voltage Light Tester: Amazon.com: Industrial & Scientific )

Or, try connecting the truck to another trailer, or the trailer to another truck.

You wrote that the previous lights worked without manually turning on the truck lights. Did this truck come with factory installed trailer lighting? If so the trailer lights will reflect the status of the truck's lights. Were the earlier trailer lights the same type as the current lights (wattage, LED, incandescent) ? If the truck trailer wiring was aftermarket the wire connections are highly suspect.

BTW: A standard 4-wire trailer connector has a ground wire, a tail light-running lights wire, a left-hand brake/directional light wire, and a right-hand brake-directional light wire.

 

[ljjhouser]

Thanks. I will give that a try. I guess the confusing part is the white wire on the trailer harness at each light location. This, to me, is ground or neutral but your comment earlier leads me to believe that the wire wire is actually is a substitute for brown for the tail lights. (running light) Then the second wire (black in my case) of the trailer harness would go to the yellow wire on the left side and green on the right side.

You mentioned the term "neutral." That may make this confusing. There is no neutral, only ground in a simple trailer wiring setup such as this. Most people associate a neutral wire with the white wire on 120v circuits. Those circuits can have both neutral and ground. They may or may not terminate at the same block in the entrance panel. I am glad you finally got it solved. best wishes, Larry

 

[ljjhouser]

Hopefully, wiring all lights to a ground wire connected to a single point means you only need to check the single point where the wire is grounded (ground wire to connector) to solve a ground problem. And if the connections are soldered and sealed, that will be the only place to check for grounding problem on the trailer. And if only one or two lights fail, You will know it is not usually the ground. If they are all out, check the ground point. If you ground to the frame, you may continue to have problems with separate ground problems with random lights.

 

[Bob Rooks]

Do you mean brake lights don't work unless headlights are on? I'd check your truck on a different trailer and check the trailer on a different truck.

I do know newer Fords sometimes have problems with low impedance LED lights. The "smart" brake controller isn't smart.

Also, it could be ground. Run a ground wire externally to each light in turn to verify. On my trailer, I ended up with an intermittent problem. Eventually I figured out a ground problem. Its a tilt trailer and the trailer harness was grounded to the tongue and the lights to the frame. The frame/tongue pivot is old and corroded. The fix was a ground jumper at that location.

Many Fords do not have a flasher unit. My '08 F350 turn signals are controlled by the ECM. Found that out when I went to install LED's. Have to use external resistors on all four corners, but that also compensates for LED trailer lights.

 

[bcp]

Do brake lights still work with ignition off?

Bruce

 

[WranglerX]

It the end it is just a "current loop" with electrons flowing from source (generator/alternator/battery) then trough "lamp" (incandescent/LED) and then though "switch" (headlamp/turnsignal) and back to source... To confuse the issue electron flow is from negative side power source to positive s

ide of power source...

 

[bcp]

To confuse the issue electron flow is from negative side power source to positive side of power source...

It makes sense as the negative side is losing electrons while the positive side is gaining electrons.

Bruce