Tech Tips

Load Resistors & Canbus Decoders
HE-LR Load resistors and decoders
When upgrading headlight bulbs on newer vehicles, it is important to balance the circuit so
that the replacement LED bulbs are not miss detected as blown. This issue is caused by
the reduced current draw and circuit load that the LED present to the system compared to
the factory filament bulbs. If this error occurs, some of the common issues that appear are a
bulb out warning light on the dash, a check engine code, and in some cases no light output
due to the vehicle shutting down power to the circuit. All of the replacement bulbs in the
Heise line have special circuitry to prevent these issues from occurring; but due to the
variety of requirements by different vehicles, occasionally additional parts are needed to
balance the circuit.
Headlight replacement bulbs
Headlight replacement bulbs have two different part options to balance the circuit, and can
be used independently or in conjunction.
Canbus decoders (HE-xxxxD) are the go to staple for balancing headlights. They are plug
and play, and are installed in between the vehicle and the replacement bulb (one per bulb).
Heise offers decoders for all headlight bulb sizes carried in the line.
Load resistors (HE-LR) can also be used to balance the circuit. They are installed across
the positive and negative leads of the light bulb. The load resistor is not directional and can
be installed either way. If being used along with canbus decoders, the load resistor is
placed between the vehicle and the decoder (one per bulb). Please note that load resistors
can become hot during use and should be mounted to a solid metal surface to prevent
damage to wires or plastic parts.
Canbus decoders
Load resistors
LED Bulb
Canbus Decoder
Load Resistor
Vehicle
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