Bike Rack LED lighting problem

[PaPaC]

I installed a LED light bar on a bike rack because the bikes block out the tail lights. My 2022 Bronco Sport has the tow package with the factory installed 4 pin connector. The running lights and brake lights work fine but the turn signals do not work properly and I get the hyper flash on the dash when I use a turn signal. I have tried the with resistors but the lights won’t work at all.

Interestingly, everything works fine with the auxiliary power on. The problem exists only when the engine is running. Other trailers with regular incandescent bulbs work fine. Looking for any insight…

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[Dude]

The current with LEDs is insufficient for the Bronco Sport BCM so the BCM thinks a bulb is burned out thus the hyper flash

Possibly the wrong value resistor was used or the resistor was incorrectly installed

What value resistor & it’s wattage was used and do you happen to have a pic showing how it was installed

 

[PaPaC]

Used 50w resistor. (Really could find no information about what value to use). No pic showing how it was installed, but I tried them both ways and got the same result. I put one resistor in each wire except for the ground.

 

[Dude]

Used 50w resistor. (Really could find no information about what value to use). No pic showing how it was installed, but I tried them both ways and got the same result. I put one resistor in each wire except for the ground.

Resistor goes in parallel with the LED so across the leads of the LED

 

[Dude]

Here are a couple of calculations, from my owners manual the rear turn signal is 16W:

Voltage: 12V
Incandescent bulb Power: 16W
Resistance = V² / P = 144 / 16 ≈ 9 ohms so an 8 ohm or 10 ohm 50W resistor

Many rear turn signal bulbs are 21W so here is the load resistor calculation for that:
Voltage: 12V
Incandescent bulb Power: 21W
Resistance = V² / P = 144 / 21 ≈ 6.8 ohms so a 6 ohm 50W resistor

The load resistor goes in parallel with the LED so across the leads of the LED

The load resistor will get warm so should be a metal clad resistor as shown in your pic and bolted to the clean metal frame of the vehicle (away from any plastic or anything else that could be damaged by heat) in order to dissipate heat from the load resistor

Your pic shows the resistor is 6RJ so likely that is 6 ohm - if the incandescent bulb you took out is the WY16W it is a 16W bulb so the load resistor should be 10 ohm or 8 ohm (50W).

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