Flashers, Relays

Repco offers a comprehensive range of relays to suit standard replacements, accessory installations, and dual battery systems. Whether you need a basic 12v relay for lighting upgrades or a heavy duty voltage sensitive relay for auxiliary battery control, Repco’s range covers everyday passenger vehicles, 4WDs, trade vehicles, and commercial applications.

Available options include 4 pin relay and 5 pin relay configurations, 40 amp relay models for common accessory circuits, compact mini relay and micro relay designs for tight fuse box layouts, and high capacity 100 amp relay units suited to battery management systems. Repco also stocks trusted brands such as Narva relay products, along with flasher relay and indicator relay solutions for signalling systems.

Understanding Automotive Relays and Their Function

A relay switch allows a low current circuit to control a higher current load safely. When energised, the internal coil closes or opens electrical contacts. This design protects dashboard switches, control modules, and factory wiring from excessive load.

Repco’s selection of relays includes standard plug-in designs that match original equipment layouts, as well as aftermarket solutions suited to custom wiring projects. Whether you are replacing a faulty fuel pump relay, upgrading a headlight relay for improved voltage supply, or installing a starter relay in a custom build, selecting the correct rating and configuration is essential.

Voltage Sensitive Relays for Dual Battery Systems

What is a Voltage Sensitive Relay?

A voltage sensitive relay, commonly known as a vsr or vsr relay, automatically links and isolates batteries depending on system voltage. Repco’s range of voltage sensitive relay 12v units are designed for dual battery setups in touring vehicles, service vehicles, and recreational applications.

When charging voltage rises above a preset level, typically between 13.2V and 13.7V, the vsr closes and allows both batteries to charge. When voltage drops below a safe threshold, the relay isolates the starting battery. This ensures accessories powered by the auxiliary battery cannot drain the battery needed to start the engine.

Repco’s higher capacity options, including 100 amp relay models used in battery management systems, are suitable for setups powering fridges, lighting, compressors, and inverters. For heavy vehicle applications, a 24v relay or 24v solenoid may be required instead of a 12v solenoid.

Common Relay Types Available at Repco

Repco’s range includes standard 12v relay units rated at 20, 30, and 40 amps, suitable for cooling fans, horns, and lighting circuits. A 40 amp relay is commonly used when installing driving lights or upgrading factory headlight relay circuits to reduce voltage drop.

For indicator systems, Repco stocks flasher relay and flasher unit options, including electronic flasher solutions compatible with LED upgrades. If you are converting to LED indicators, an led flasher relay prevents rapid flash rates caused by reduced load. Traditional systems may use a flasher can, while modern replacements use solid-state designs.

Repco also supplies glow plug timer modules for diesel engines, allowing controlled pre-heat timing. While not a simple relay, it performs a similar switching function within a timed circuit.

Compact mini relay and micro relay designs are available for vehicles with limited fuse box space. These relays provide the same switching function as larger units but in a reduced footprint. Matching the physical size and terminal layout ensures correct fitment.

What is the difference between a 5 pin and a 4 pin relay?

Repco’s 4 pin relay models are normally open relays used in straightforward on-off circuits. They are commonly installed in fuel pump relay circuits, headlight relay upgrades, and accessory wiring.

A 5 pin relay includes a normally closed contact, allowing changeover between two circuits. Repco stocks both configurations, making it easier to match factory specifications or design custom wiring setups. Choosing the correct relay prevents unnecessary rewiring and ensures consistent operation.

Where Relays Are Used in Automotive Systems

Where are 12v relays used on my vehicle?

Repco’s range of relays supports a wide variety of applications. A starter relay controls current to the starter motor solenoid. A fuel pump relay manages fuel delivery in electronically controlled engines. A headlight relay upgrade can improve lighting output by reducing resistance in factory wiring.

Cooling fans, air conditioning compressors, auxiliary driving lights, horns, and aftermarket accessories all rely on a properly rated 12v relay. Indicator relay and flasher relay units manage turn signal timing, while an led flasher relay ensures compatibility with modern lighting upgrades.

For custom installations such as dual battery systems, air compressors, or winches, Repco’s heavy duty relay switch options provide reliable load control when installed with appropriate fusing and cable sizing.

Diagnosing and Replacing Faulty Relays

How do I know when a relay is faulty on my vehicle?

If an accessory stops working but the fuse remains intact, a faulty relay may be the cause. A failed fuel pump relay can prevent engine start. A defective headlight relay may result in intermittent lighting. Clicking sounds without operation, or no clicking at all, can indicate coil or contact failure.

Repco stocks replacement relays across multiple amperage ratings and configurations, allowing you to match specifications accurately. Checking terminal numbering, voltage rating, and current capacity before replacement helps prevent repeat faults.

Cost and Value Considerations

How much does it cost to replace a relay?

Standard replacement relays from Repco, such as a 4 pin relay or 5 pin relay, generally range from $10 to $40 depending on brand and rating. Specialised units, including a voltage sensitive relay 12v or high current 100 amp relay, will be priced higher due to increased capacity and protective features.

Because relays are relatively affordable, replacing a suspected faulty unit is often a practical first step in diagnosing electrical issues. Repco’s broad range ensures you can source compatible replacements for both older and late model vehicles.

Selecting the Right Relay from Repco

When choosing from Repco’s range of relays, confirm system voltage, required current rating, pin configuration, and mounting style. For lighting upgrades, a 40 amp relay is commonly sufficient. For dual battery installations, a properly rated vsr provides automatic battery isolation. For heavy vehicles, confirm whether a 24v relay or 24v solenoid is required.

Repco’s selection includes trusted narva relay options, compact mini relay and micro relay designs, flasher relay replacements, and heavy duty battery management relays. Matching the correct relay to your application ensures safe switching, reliable performance, and protection of your electrical system.

To support your installation or repair, explore complementary categories including battery cables and terminals, automotive fuses and circuit protection, and dual battery system accessories. Pairing quality relays with correct wiring and protection components ensures your electrical upgrades operate reliably and safely.