Picture of simple leaded LED's

Wiring an LED

We got another great question from a customer today.  This one came in through our Facebook page.

“I’m going to be running LED headlamps and taillights on my Infinitybox-equipped car. Can you write-up a blog on the changes I’ll need to make in my wiring?”

Here are the changes that you need to make when wiring an LED light with the Infinitybox system:  absolutely nothing.

Our POWERCELLs turn things on and off including fans, ECU’s, pumps and lights.  Lights come in basically two flavors: incandescent and LED.  Incandescent lights were the original creation of Thomas Edison.  Up until a few years ago, they were used for all of the lights in cars including headlights, running lights, interior lights, brake lights and turn signals.

The trend in automotive lighting is towards LEDs or light emitting diodes.  This link will take you to a Wikipedia page talking about how they work.  LED’s have two main advantages of incandescent light bulbs.  First, they have no filaments or fragile parts so they last a long time.  Second, they are much more efficient than incandescent bulbs.  This means that they consume much less current to get the same level of brightness.

To go back to the question, you can connect an LED light in the place of an incandescent bulb and it will work correctly when connected to an Infinitybox POWERCELL.  The other question that we usually get related to LED’s is “do I need a load resistor when using LED turn signals?”.  The answer again is “no”.

Traditional turn signal flashers work by drawing current through a heating element within the flasher.  The flashers are expecting a certain amount of current being drawn by an incandescent bulb.  When you change to LEDs with a traditional turn signal flasher, you needed to add a load resistor that draws current through the circuit.  This compensates for the reduced current flowing through the LED.

With the Infinitybox system, you don’t need the load resistor to get your turn signals to work correctly.  We do the flashing of the turn signals and 4-ways through the processor on the POWERCELL.  The flashing does not depend on the amount of current flowing to the bulb.  To the POWERCELL, there is no difference between an incandescent bulb or an LED light.

To round out this question, there is one thing that you may need to do when wiring an LED into your Infinitybox system.  As we mentioned above, LEDs are much more efficient than their incandescent cousins.  It takes very little current to turn them on.  LEDs from different manufacturers are more or less efficient, depending on the materials that they may use.

Our POWERCELLs leak a very small amount of current out of the outputs.  We use this as part of our diagnostic system.  Depending on the efficiency of the LED, this diagnostic current may make the LED’s glow dimly when the light is off.  To eliminate this, you can simply connect a 10K (10,000 ohm) resistor between the POWERCELL output wire and ground.  An 1/8 Watt resistor or larger will be fine.  This picture shows you how to wire this in.

Picture of wiring diagram showing how to wire a bypass resistor with LED lights

Picture of wiring diagram showing how to wire a bypass resistor with LED lights

This bypass resistor shunts the diagnostic current through the resistor around the LED.  You can pick up a 10K resistor on-line.

You can download a PDF of this wiring diagram by clicking this link.

Please give our technical support team a call if you have questions about this post.

Wiring a switch with an indicator

The inputs to the Infinitybox MASTERCELL are very easy to use.  You simply connect the input wire to a switch and ground the other side.  When you turn on the switch, the input gets connected to ground, which tells the MASTERCELL to turn on a POWERCELL output.  You can get your ground connection from either the ground wires that we supply in the MASTERCELL harness or you can connect them right to ground on your chassis.  This approach reduces the total number of wires that you need to go to your switch and lets us a very small gauge of wire to connect to the switch.

Sometimes, a customer wants to use a switch that has an indicator light built into it.  That is very easy to do with the addition of a few simple components.

Here is an example of a popular switch that a lot of our customers use.  It is a simple, round toggle switch.  There is an LED built into the switch that can light up the rocker when the switch is in the on position.  You can purchase a switch like this from Waytek by clicking this link.

Image showing how to wire a switch with an Indicator Light to the Infinitybox MASTERCELL

Image showing how to wire a switch with an Indicator Light to the Infinitybox MASTERCELL

The important thing to note here is that you MUST install a diode in the input wire from the MASTERCELL to the switch.  This should be a 1N4001 diode and can be purchased on-line.  Please note that the direction of the diode is very important.  The stripe on the diode should be on the side of the wire that is connected to the switch, not the side going to the MASTERCELL.

You can get your 12-volts from anywhere in the car.  If you want, you can use Ignition power from the POWERCELL for the indicators.  That way your switches will only light when the ignition to the car is on.  Alternately, you can wire this directly to a constant power supply from the battery.

Also note that the polarity of the wiring to the switch is important.  Make sure that you are looking at the wiring diagram that came with your switch and referencing our wiring diagram.

If you follow these simple instructions, your switch indicators will light up when you turn on the switch.  You can download a PDF version of this wiring diagram by clicking this link.

If you have any additional questions about this wiring diagram, please reach out to our technical support team at (847) 232-1991 or email us at  You can also contact our team by clicking this link.