Relays, 12V, 24V, 30A and 40A for Truck, Jeep and Car Wiring

What This Relays Collection Covers

This collection helps builders control higher current loads with a low current trigger circuit. It includes common relay related components for auxiliary lighting, pumps, fans, horns, accessories and switched circuits where the correct wire size, fuse protection and installation method matter.

Relay Ratings and Terminals

Choose voltage and current ratings that meet or exceed the expected load. Confirm terminal layout, pin count, normally open or normally closed operation and whether the design uses a diode or resistor suppression circuit.

Sockets, Pigtails and Harnesses

A matched relay socket or pigtail makes a serviceable installation and helps prevent loose connections. Use terminals sized for the wire gauge and protect every circuit with the appropriate fuse or breaker.

Switches and Trigger Inputs

Rocker switches, ignition sources, sensors and Hobbs switches can provide the low current trigger for a relay. Plan the trigger path so the accessory cannot operate when it should be off.

Lighting and Accessory Circuits

Relays are useful for light bars, auxiliary lamps, pumps, fans and other electrical accessories. Route wiring away from heat, moving parts and sharp edges, then secure it with proper protection.

Top Relays Brands

• Bosch, proven automotive relay designs
• Hella, lighting and electrical control components
• Painless Wiring, wiring harnesses and electrical kits
• sPOD, accessory control systems
• DeatschWerks, pressure switch and fuel system controls
• Nitrous Express, high current electrical accessories
• Snow Performance, pump controllers and wiring
• DragonFire Racing, UTV switch accessories
• Twin Power, ignition switch hardware
• Bussmann, circuit protection components
• Blue Sea Systems, electrical distribution products
• ARBs, accessory wiring solutions
• Rugged Ridge, Jeep electrical accessories
• KC HiLiTES, auxiliary lighting circuits
• Rigid Industries, LED lighting control hardware

How to Choose the Correct Relays Part

• Confirm the vehicle voltage and the accessory current draw
• Choose a relay with a sufficient continuous current rating
• Match pin layout and terminal count to the harness or socket
• Use a fuse or circuit breaker close to the power source
• Size wire gauge for current, circuit length and voltage drop
• Choose weather resistant sockets for exposed installations
• Use a diode protected relay only where the circuit requires it
• Plan a clean ignition, switch or sensor trigger source
• Mount relays away from exhaust heat and standing water
• Test operation with a multimeter before finalizing the loom

Common Questions

What does an automotive relay do?

A relay uses a small trigger current to switch a higher current circuit for an accessory such as lighting, a fan or a pump.

What is the difference between 30A and 40A relays?

The rating is the maximum current the relay contacts are designed to handle. Select a rating that safely covers the actual load.

Can I use a 24V relay on a 12V vehicle?

Not normally. The coil voltage must match the vehicle control voltage for reliable operation.

Do I need a fuse with a relay?

Yes. A relay does not replace circuit protection. Install a correctly rated fuse or breaker near the power source.

What is a relay socket?

A relay socket holds the relay and provides terminated wire connections for a cleaner serviceable wiring installation.

What is a relay harness?

A relay harness combines a socket and prewired leads to simplify wiring for common auxiliary circuits.

Can a relay control LED lights?

Yes. Match the relay, wiring and fuse to the total LED current draw and follow the lighting manufacturer instructions.

What is a Hobbs switch used for?

A Hobbs switch changes state at a selected pressure and can trigger a relay for a pump, fan or other accessory circuit.

Why does a relay click but the accessory not run?

The relay may be receiving a trigger while the high current side has a wiring, fuse, ground or load problem.

Should relays be mounted under the hood?

They can be mounted there when protected from heat, water and vibration. Use sealed components for exposed locations.

Why Buy Relays from Black Ops Auto Works

Black Ops Auto Works stocks 33 Relays SKUs with real fitment data, competitive pricing and support from staff who build these vehicles themselves. Products are filterable by year, make, model, trim, engine and drivetrain to confirm the correct application before ordering.

For focused shopping, browse our Wiring Harnesses, Switch Panels, Sensors, Lighting, Battery Accessories.