Would A Load Resistor Solve This LED Issue? (1 Viewer)

[DerbyDad03]

Greetings from a new member. I'm hoping you folks can diagnose a problem for me.

I have read the info on using a load resistor to eliminate hyper flashing of LED tail lights in cases where a dual filament bulb (e.g. 1157) is replaced with an equivalent LED. However, I have a different LED related problem on my Haulmark cargo trailer.

My trailer has 2 dual filament tail lights (1157) and 6 markers lights (194). Each side has an amber marker light at the top front and red marker lights, top and bottom, at the rear.

I replaced all of the bulbs with LED equivalents. The trailer wiring is a flat four plug.

With the 1157 LED equivalents in the tail lights and the vehicle lights on, everything works properly. The turn signals flash at the proper speed, all the lights, LED side markers included, are nice and bright, brake lights and hazards are fine.

However, things get weird when the vehicle's lights are off. This started after the LED's were installed. When I use a turn signal, the corresponding tail light flashes nice and bright, but the opposite tail light and all 4 red side marker lights flash at about half brightness. The amber side markers at the front do not come on.

When I use the hazards, the tail lights flash brightly, but the red side markers also flash at half brightness. The brakes do the same thing: Tail lights are fine, red side markers come on at half brightness.

As a test, I replaced the tail light LEDs with the standard incandescent 1157's and everything went back to normal, even with the vehicle lights off. No flashing side marker lights, no side markers on with the brake, etc.

So obviously, the 1157 LED equivalents are causing the problem. Would adding load resistors on the wires to the flashing filament solve this problem?

Thanks for any advice that you have to offer.

 

[ntsqd]

Give all of the light fixture grounding on the trailer a thorough going-over. Usually this sort of thing is caused by poor grounding resulting in the current going 'backwards' thru another element to find a ground. In your case it takes very little voltage to turn on the LEDs, so it wouldn't take much of a poor ground to create that potential.

As a matter of habit from lessons learned I now wire trailer lights with a dedicated ground wire all of the way back to the receptacle on the tow rig. I do not rely on the frame for any grounding. Treat the trailer like its a fiberglass boat when wiring it.

 

[DerbyDad03]

Give all of the light fixture grounding on the trailer a thorough going-over. Usually this sort of thing is caused by poor grounding resulting in the current going 'backwards' thru another element to find a ground. In your case it takes very little voltage to turn on the LEDs, so it wouldn't take much of a poor ground to create that potential.

As a matter of habit from lessons learned I now wire trailer lights with a dedicated ground wire all of the way back to the receptacle on the tow rig. I do not rely on the frame for any grounding. Treat the trailer like its a fiberglass boat when wiring it.

Thanks. I'll give the grounds a check/rewire once the weather warms up. For now, I'll just keep the vehicle lights on
all the time which is what I usually do anyway.

Thanks again.