LED 3rd brake light
#1
LED 3rd brake light
I just bought and installed an LED 3rd brake light, and works great however, when the parking/headlights are on, the 3rd brake light is also on but at reduced power, is this normal? any way to get rid of this?
#5
Ungrounded Moderator
iTrader: (4)
The issue is similar to that of using LED bulbs in turn signals - they have so little resistance and draw so little current that connected systems (the turn signal flasher or in this case the cruise control system) don't "see" them as being there. It isn't a current back flow issue so diodes won't help (LEDs are diodes anyway) but adding enough resistance to simulate a standard incandescent bulb should fix the problem. With the third brake light, adding resistance will stop the dim glow when not in use and will also fix the problem of the cruise control not activating.
The easiest way to do that is to buy one of those load balancing resistor kits intended for turn signal use. You can find them for $5 or $6 online and at most auto parts stores. The kit will include two resistors in heat sink housings with a wire coming out of each side and some Scotch Lock style connectors. Take one of the resistors and use the connectors to attach the resistor so that it joins the two factory wires at the third brake light. Do not cut wires or disconnect the factory plug - just splice the two ends of the resistor between the two wires of the brake light.
The easiest way to do that is to buy one of those load balancing resistor kits intended for turn signal use. You can find them for $5 or $6 online and at most auto parts stores. The kit will include two resistors in heat sink housings with a wire coming out of each side and some Scotch Lock style connectors. Take one of the resistors and use the connectors to attach the resistor so that it joins the two factory wires at the third brake light. Do not cut wires or disconnect the factory plug - just splice the two ends of the resistor between the two wires of the brake light.