LED turn signal hyper flash: the fix

Fit LED turn signal bulbs and many cars start blinking at double speed. Nothing is broken — the car just thinks a bulb is out. Here is why and how to fix it.

Why it happens

Car flasher circuits monitor current. A halogen turn bulb draws around 2 amps; an LED draws a fraction of that. The car reads the low current as a failed bulb and speeds up the blink to warn you — hyper flash. Some cars also show a bulb-out message.

Fix 1: load resistors

• Use one 50W 6Ω resistor per LED turn bulb.
• Wire it in parallel: one lead to the turn-signal wire, one to ground.
• Use the splice taps or solder and heat-shrink.
• Mount it on bare metal; it gets as hot as a halogen bulb.

Fix 2: LED flasher relay

On many older cars with a plug-in flasher relay, an LED-compatible relay fixes all four corners at once with no wiring. Check whether your car's flasher is a separate plug-in unit or built into the body control module.

Which to choose

Resistors work on almost any car and fix bulb-out warnings too. A relay is quicker if your car has a replaceable one. Either way, keep the LED bulbs — they still light faster and last far longer than halogens.