Why Use Relays?
A relay is an electrically controlled switch that allows you to use a small amount of current to control a larger current flow without physically interacting with that larger current. This translates to several benefits for you.
For one, a relay allows you to control larger currents than your dash switch is rated for. For example, a large off-road lighting setup or bank of cooling fans can easily pull 30 or 40 amps. But if your dash switch is only rated for 20 amps it won’t be able to handle the power needs of the circuit. So instead of wiring all of the power through the switch, and burning down your car, you can wire the main power through a properly rated relay and use the dash switch to control the relay. Cleaner and safer.
Relays also allow you to activate multiple different circuits with a single switch. Since the power draw on the low current side of the relay is so low, multiple relays, each controlling a separate circuit, can all be controlled by a single switch. You might see something like this on a compressor and fan application or in a power door lock circuit.
Relays even save you money. Electrical components and wires designed to handle large loads are significantly more expensive than their lower-rated cousins. Using a relay reduces the number of high-rated components needed to complete the job. The switch can be smaller, the length of heavy-duty wiring needed is minimized, and the possibility of an accidental high-current short to ground is greatly reduced.
No burnt switches, more control, and less money; relays make everyone happy. Take a look at our wide section of automotive relays and waterproof relay boxes and see how they can help you design a better, safer and cheaper circuit.