Are Load Resistors Required when Adding LED Lights to a Trailer

Question:

How hot do the load resistors get? Similar to the heat of an incandescent bulb? If I wrapped the resistor with some type of insulation, how would it affect the performance? I read that the load of the resistor is about 2 amps. Should one resistor be installed in close proximity to each blinker? I noticed you sell ceramic resistors. Would this eliminate the possible heat build up, or simply last longer? I have several vehicles and trailers I would upgrade to leds. I really like the brightness, very distinct on-off and durabilityespecially on my trailers. Thank you for your time. When I find a company that can help like this as well as the parts, I stick with them.

asked by: Kendall S

Helpful Expert Reply:

You may not even need load resistors to switch to LED lights. The best thing to do is to try the lights without load resistors first. No need to purchase something you may not need until you know need it.

Load resistors such as # DI34ZR dissipate heat through the body of the resistor. Wrapping them with insulation would prevent them from dissipating heat properly. You could put them in a battery or junction box though.

Load resistors increase the amperage draw on a circuit. If you are experiencing hyperflash on the turn signals or the LED lights do not have enough draw to activate a load resistor will help. You would need one per affected circuit. I have linked the instructions for you to view.

expert reply by: Michael H

Kevin G.

7/16/2020

I have a 2020 Alaskan Camper (truck camper). Also a 2020 GMC Sierra 3/4 ton gasser. My camper only has running lights which are LED. For some reason the do not work. When I plug in my utility trailer all the lights work. Do I need to add a resistor to my camper? Thanks

Chris R.

7/21/2020

I honestly don't think the LEDs are the issue. I'm assuming the truck camper is being plugged into the same connector as the utility trailer? If not the same connector, it's certainly using the same circuits on the Sierra. I would test the camper wiring just behind its plug to see if you get any power when hooked up and the tail lights are on. I'm thinking there may be an issue with the camper's harness.

Thomas P.

8/25/2020

@ChrisR I tried everything you have described. Tried the lights with 3 vehicles. They have the same issue. I have tested them with tester and they always work. When using lights everything works but when using the running lights it turns off. On the side of the led there is a running light on but turn signals don't work. I installed a led light to connect to the lights but they don't turn on. They actually did work when having running lights at one time but they were dim. I have cleaned the ground wire connectors and frame. I have sanded it. I have made a new hole for ground with no luck. Put new wires but they didn't work so I reverted to old ones. Tried the ground from led lights from where they are connected to the frame and they don't work. Will a resistor give it more power.

Jon G.

9/1/2020

Yes, a load resistor will give it more power. Some pickups have problems noticing that a camper is connected when the camper only has a few LED lights so the "smart" system doesn't send back power. Adding load resistors makes it look like incandescent lights to the truck and so it then acknowledges that something is connected and it sends power.

See All (4) Replies to Kevin G. ∨

Jeff F.

7/19/2020

We hook up to tow car and brake lights and blinkers work but our running lights turn on and immediately go off. What could be causing this? We used same trailer harness and tried behind other vehicles and it worked perfect!

Chris R.

7/21/2020

If the trailer worked with other tow vehicles you at least know the issue is on the vehicle side. I'm not sure what type of trailer harness is installed, but make sure it's main ground wire is still securely attached to clean, bare metal. A weak ground can definitely lead to issues like this.