Hyper Flash, Load Resistors and Indicator Compliance
This page explains why turn indicators flash rapidly after an LED upgrade, a behaviour commonly called hyper flash, and what it means for compliance with the Australian Design Rules. It covers the technical cause, the legal flash rate required for turn indicators, the two correct ways to restore that flash rate, and what to check after installation. It is written for owners upgrading the indicators on a Toyota LandCruiser 70 Series and other vehicles, and for anyone who needs the vehicle to pass a roadworthy inspection after an LED change.
What Hyper Flash Is
Hyper flash is the term for a turn indicator that flashes noticeably faster than normal after a globe change, typically at twice the usual rate or more. It usually appears immediately after incandescent indicator globes are replaced with LED units. The indicator still illuminates, but the rapid flashing is both a sign of an electrical mismatch and, in most cases, a compliance problem.
The behaviour is not a fault in the LED globe itself. It is the vehicle's flasher system responding to a change in electrical load in exactly the way it was designed to. Understanding that design is the key to fixing the problem correctly rather than masking it.
Why LED Indicators Cause Hyper Flash
A traditional incandescent indicator globe draws a relatively high current, commonly in the order of 1.5 to 2 amps each. The factory flasher unit, or the body control module that performs the flasher function in newer vehicles, monitors the current flowing through the indicator circuit. This current monitoring is how the vehicle detects a blown globe.
When a globe fails, the current draw on that side drops. The flasher detects the reduced load and deliberately doubles the flash rate to alert the driver that a globe has failed. This is the standard bulb-out warning behaviour built into the vehicle, and it is a safety feature in its own right.
An LED indicator draws far less current than the incandescent globe it replaces, often only a fraction of an amp. From the flasher's point of view, this low current draw looks identical to a blown globe. The system therefore does what it was designed to do and doubles the flash rate. The result is hyper flash on every LED indicator, even though all the globes are working correctly.
What ADR 13 Requires for Flash Rate
ADR 13/00 (Installation of Lighting and Light-Signalling Devices) governs how lamps and indicators are fitted and how they must operate on a vehicle. Among its requirements, a direction indicator must flash at a steady rate of 60 to 120 flashes per minute. That is between one and two flashes per second, with a consistent on and off cycle.
Hyper flash takes the indicator well above this range. A rate that exceeds 120 flashes per minute does not meet the requirement and renders the indicator installation non-compliant with the applicable ADRs for vehicle lighting. A flash rate that sits outside the legal band is a defect that can fail a roadworthy inspection in any Australian state or territory.
There is a safety dimension as well as a legal one. The flash rate band exists so that a turn signal is unmistakable to other road users and is clearly distinguishable from a hazard, a brake lamp, or a steady marker lamp. An indicator flashing at three or four flashes per second reads as a fault or a hazard rather than a clear turn intention, which reduces the clarity of the signal for following and oncoming traffic. Restoring the correct rate is therefore about being understood on the road as much as it is about passing inspection.
Problem, Cause and Fix
The symptoms that appear after an LED indicator upgrade almost always trace back to the same underlying current mismatch. The table below sets out the common ones, what causes each, and the correct remedy.
| Problem | Cause | Fix |
|---|---|---|
| Hyper flash (indicator flashes roughly twice the normal rate or faster) | LED draws far less current than the original globe, so the flasher reads it as a blown globe and doubles the flash rate | Fit a load resistor on the affected circuit to restore the original current draw, or fit a purpose-made anti-hyper-flash module or electronic flasher |
| Bulb-out warning on the dash or in the driver display | The body control module monitors indicator current and reports the low LED draw as a failed globe | Restore correct load with a resistor, or use an LED-compatible flasher or canbus-compatible module that does not rely on current to detect a globe |
| Flash too fast on one side only | Only one side was converted to LED, or one resistor is missing or not making contact, so the loads are unequal | Apply the same solution to both sides so the load is matched, and confirm every resistor or module connection is secure |
| Indicator works but flashes irregularly or intermittently | Loose connection, poor earth, or a resistor that is overheating and dropping out | Check and clean connections and earths, confirm the resistor is the correct value and is mounted to dissipate heat properly |
Load Resistors
A load resistor is a component wired in parallel across the indicator globe or its wiring. It draws additional current so that the total load on the circuit matches what an incandescent globe would have drawn. With the correct load restored, the flasher no longer reads the circuit as a blown globe and returns the flash to the normal rate.
Load resistors are an effective and widely used fix. They are most often specified at 6 ohms and 50 watts for a circuit replacing a standard indicator globe, though the correct value depends on the original globe and the vehicle. The main practical point to understand is that the resistor converts the saved current into heat. A 50 watt resistor can become very hot in normal operation, which has direct consequences for how it must be installed.
Installing a load resistor correctly
- Wire the resistor in parallel with the indicator, connecting it across the signal wire and earth for that lamp, not in series with the globe.
- Fit one resistor per indicator circuit that has been converted to LED. Front and rear on the same side usually flash from the same circuit, so confirm how your vehicle is wired before deciding how many are needed.
- Mount the resistor on a clean bare metal surface that can act as a heat sink, away from wiring looms, plastic trim, fuel and brake lines, and anything else that can be damaged by heat.
- Do not mount the resistor against painted or coated surfaces that can scorch, and keep it clear of any area where it could contact a hand during normal servicing.
- Use the connection method and crimps rated for the current involved, and ensure the earth is solid. A poor earth produces the irregular flashing described in the table above.
Anti-Hyper-Flash Modules and LED Flashers
The second correct fix is to address the flasher rather than the load. A purpose-made anti-hyper-flash kit, an LED-compatible electronic flasher, or a canbus-compatible module changes how the system decides the flash rate so that it no longer depends on the low LED current.
This approach has advantages over resistors. It does not generate the heat that a load resistor does, it preserves the reduced current draw of the LED conversion, and a vehicle-matched module avoids the dashboard bulb-out warning that resistors alone may not clear on vehicles where the body control module performs the monitoring. The correct module type depends on the vehicle and on whether the flasher function is handled by a standalone flasher unit or by the body control module, so the solution must be matched to the specific vehicle.
Whichever method is chosen, the objective is the same and is set by ADR 13/00. The indicators must flash at a steady 60 to 120 flashes per minute, with no false bulb-out warning, on both sides.
Confirming Correct Installation
After fitting either a load resistor or a module, confirm the result before relying on the vehicle on the road or presenting it for inspection.
- Operate the left indicator and confirm the flash rate looks normal and steady. Operate the right indicator and confirm it matches. Both sides should flash at the same rate.
- Confirm there is no bulb-out or globe-failure warning showing on the dash or in the driver display with the indicators operating.
- Operate the hazard lights and confirm all indicators flash together at a steady rate.
- Check that the indicator self-cancels correctly after a turn where the vehicle has that function.
- Where a resistor is fitted, run the indicators for a period and confirm the resistor and its surrounds are not contacting anything heat-sensitive and that the flash rate stays steady once the resistor is warm.
If the flash rate is still fast, a connection is loose, the resistor value is wrong, or only one side has been addressed. If a bulb-out warning persists after resistors are fitted, the vehicle most likely needs a module-based solution because the body control module is still monitoring the circuit.
Indicator Upgrade Products
PVS Automotive supplies the parts to convert indicators to LED and to keep the flash rate compliant. Products are matched to the specific vehicle and designed to be plug and play.
- For the LED conversion itself, see the LED indicator globes, which replace the factory incandescent indicator globes.
- To resolve hyper flash and bulb-out warnings, see the indicator load resistor wiring kit, which restores the correct current draw so the indicators flash at the legal rate.
For background on choosing and fitting LED indicator globes and what to expect after the change, see the LED indicators topic in our compliance resources. If your specific variant or build year is not listed for a given part, contact our team before ordering so the correct solution for your wiring can be confirmed.
Roadworthy and Certification
An indicator that flashes outside the 60 to 120 flashes per minute band is a defect that can fail a roadworthy inspection. So can an indicator that is the wrong colour, that does not operate, or that triggers a persistent fault. Fixing hyper flash so the indicators flash at the correct steady rate is part of keeping the vehicle's lighting compliant with the applicable ADRs for vehicle lighting and with your state roadworthy requirements.
- NSW: indicator operation is checked at inspection. Certification under VSCCS may apply where lighting changes form part of a larger modification.
- VIC: lighting is assessed at roadworthy. VASS certification may apply where the change forms part of a modification affecting safety systems.
- QLD: indicator function is checked at inspection. Contact TMR, or an Approved Person under the scheme it administers, for guidance on your specific situation.
- SA, WA, TAS, NT, ACT: refer to the relevant state or territory scheme.
For a general explanation of how the Australian Design Rules work and how they interact with state inspection, see What are Australian Design Rules? For full detail on each state's scheme, see State and Territory Requirements. Independent engineering assessment documentation is available on request to support certification and insurance disclosure in any state. Always confirm requirements with a licensed automotive engineer and your insurer, and treat any modification to your vehicle's lighting as something to disclose.
Last updated: June 2026