Adding a Third Brake Light to a Small Camper Trailer

Question:

Will the Optronic sealed streamline LED fixture work with regular incandescent taillights. Hope to use as a 3rd brakelight on small camper. Or is there a incandescent similar light? thanks

asked by: Mike

Expert Reply:

You could use light # STL79RB as a third brake light. Normally it is not recommended to mix LED lights at incandescent lights because the lights don't have voltage/amperage regulators and an incandescent light could draw too much power through an LED and burn it out.

But it would work fine in this case because in order to have a third brake light you would have to separate out the combined turn signal/brake light circuits to get a dedicated brake light only function for a third brake light.

Trailers have a combined system meaning they have one wire for left turn and brake lights and one wire for right turn and brake lights. To use a third brake light you can't just wire in to a combined circuit because it will blink with the turn signal.

You would need converter # 118158. And then you would need 2 diodes, # RM-690, to prevent back feeding. I have included a diagram showing how it should wire up. If your trailer does happen to have one wire for turn signals and a separate wire for brake lights only then you need to just splice into the brake light wire and would not need the converter or diodes.

expert reply by: Michael H