Vehicle Bulb Out Sensor Goes Off When Towing a Trailer with LED Lights

Published 04/24/2013

Products Featured in This Question

7-Way to 4-Way/5-Way Trailer Adapter for Vehicles with Lamp-Out Sensors Towing Trailers with LEDs

(159)

$24.94

Load Resistor Kit for LED Turn Signals - 50 Watts - 6 Ohm - Qty 2

(37)

$13.64

Question:

I have installed this kit on a shorelander jet ski trailer and the brake lights work fine went I use the turn signal they do not work I get a buld out warning on my dash but lights are on and brake lights work any sugestions on what could be wrong it is wired as per instructions I aslo have another trailer i pull and have not had a problem with it It is only this trailer

asked by: Dave P

Expert Reply:

The bulb out sensor indicates that you may have a BMW, Volkswagen, Porsche, AUdi, or other German vehicle. These vehicles have a problem when towing a trailer with LED trailer lights. The problem is what you have described. The LED lights do not draw enough power (in this case it is just the blinkers) and it makes the vehicle think there is a bulb out.

The fix is to use a special adapter, # C35FR, which will eliminate this problem because it adds load resistors that increase the draw on the system. (This will work even if you do not have a German vehicle, it is just that this problem first occurred with those vehicles.)

If your vehicle does not have a 7-Way connector and you cannot use this adapter, you will need to install load resistors on the brake/turn light wires on the trailer. You can use # DI34ZR. I have linked installation instructions for you.

If you have a 7-Way trailer connector but the trailer does not have a 4 or 5-Way flat trailer connector like the adapter requires, then there are 2 options. First, if the trailer has a 7-Way you can wait for the forthcoming 7-Way to 7-Way adapter coming out soon that works the same way as the adapter described above. Or, you can install load resistors on the trailer wiring.

expert reply by: Michael H