Why does my LED bulb flicker or show a bulb warning?
What is happening
Many cars monitor their bulbs electronically. They expect the current of a filament bulb; an LED's much lower draw looks like a blown bulb. Some cars also pulse the circuit to test it, which can make an LED glow faintly or flicker when it should be off.
The fixes, simplest first
- CANbus or error-free LEDs: they include a built-in load so the car sees a normal bulb. They solve most interior and number plate cases.
- Load resistors: wired across the bulb's circuit to restore the expected current. They get hot, so mount them away from plastics and wiring.
- For indicators, an LED-compatible flasher relay can be needed, because error-free does not always mean hyper-flash-free.
- If nothing works on your car, go back to the filament bulb. Some cars are very sensitive.
Interior lights are rarely the problem
Interior lights are seldom monitored, so plain LEDs usually work there. Number plate lights and indicators are the circuits most often checked. Number plate lights must stay white.
Where to buy
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Frequently asked questions
Is it safe to ignore the bulb warning?
On an interior light it is only an annoyance, but on an exterior light the warning may hide a real failure later. Fix it rather than ignore it.
Do load resistors get hot?
Yes, they turn the extra current into heat. Fix them to metal, away from plastic trim and wiring.
Why do my indicators flash fast with LEDs?
That is hyper-flash: the car reads the low current as a failed bulb. A load resistor per indicator or an LED flasher relay is the usual fix.