Where is the relay for the horn?
Typically, the horn relay sits in the vehicle’s main fuse and relay box, usually in the engine bay. Some models place it in an interior fuse panel behind the kick panel or under the dash. The exact spot varies by make, model, and year, so consult the owner’s manual or a model-specific diagram for your car.
Car horns are powered through a relay that switches a high-current circuit from a low-current horn switch. Finding the relay helps with diagnostics or replacement if the horn stops working. This guide outlines common locations and a practical method to identify the correct relay in most passenger cars.
Common locations for the horn relay
Most vehicles follow one of a few standard layouts. The following spots cover the majority of current cars in the market.
- Under-hood fuse/relay box (engine bay): Look for a relay labeled HORN or HORN RELAY near the other fuses and relays in the engine compartment's power distribution center. The lid diagram often shows the exact position.
- Inside the cabin fuse/relay panel (driver’s kick panel or under dash): Some models relocate the horn relay to a secondary fuse box inside the car; check a diagram on the panel or in the owner’s manual.
- Integrated in the main power distribution center: In certain makes (for example some GM, Ford, and Chrysler products), the horn relay is one of several relays located in a larger under-hood relay block rather than a separate module.
- Near the steering column or firewall (European and specialty brands): A few brands position the horn relay close to the steering column or behind the dash near the firewall for ease of routing.
- Motorcycles and some electric vehicles: Layouts vary; refer to the service manual for the horn relay’s exact location in non-car platforms.
These locations cover most modern vehicles, but there are exceptions. If you cannot locate a horn relay after checking these spots, the owner’s manual or a factory service manual will provide the exact location for your model.
How to locate the horn relay in your car: a step-by-step guide
Follow these steps to pinpoint the correct relay and confirm it’s the problem if your horn won’t sound.
- Gather practical references: open the owner’s manual or service manual for your year/make/model; locate the fuse/relay diagram.
- Open the exterior engine bay fuse box (and interior fuse panel, if present) and inspect the diagrams on the lid or in the manual to identify the HORN or HORN RELAY location.
- With the engine off, locate the suspected relay by its shape and color; relays are typically square or rectangular with 4 or 5 terminals.
- Trace the wiring from the horn itself to the relay; confirm that the horn wire is connected to the relay’s output terminal.
- Test or swap: with caution and the engine off, you can swap the suspected horn relay with a relay of the same type and amperage rating from a non-critical circuit to see if the horn responds. Alternatively, use a multimeter to confirm continuity and coil resistance per the manual.
- Replace if faulty: if the horn works after swapping or testing, the relay was the issue; install a new relay with the same amperage rating.
These steps help you verify the relay location and assess its functionality. If the horn still doesn’t operate after replacing the relay, the issue likely lies in the horn itself, the wiring, or the horn switch.
Manufacturer-specific notes
Some carmakers place the horn relay in a non-obvious location or integrate the horn control into a larger module. Always check the model-year-specific diagram for accuracy. In modern cars, the horn can also be controlled by the body control module (BCM) or a centralized relay block, which means direct horn relay replacement may not be possible in isolation.
Quick maintenance tips
Regular checks can prevent horn failures and make future diagnostics faster.
- Inspect the horn fuse and relay connections for corrosion or loose terminals.
- Clean any corrosion on the relay terminals and connectors; ensure snug, clean contacts.
- Keep the relay box lids closed to prevent moisture intrusion; inspect seals if present.
- When replacing the horn relay, use a unit with the same amperage rating and pin configuration.
Proper maintenance helps ensure reliable horn operation and eases future troubleshooting by narrowing down faults to the horn or associated wiring rather than the power supply.
Summary
In most cars, the horn relay sits in the engine bay fuse/relay box, though some models place it inside the cabin or in a centralized relay block. To locate it, consult your owner’s manual or service diagram, then follow a step-by-step approach to identify, test, and replace the relay if needed. If diagnosis stalls, a professional technician can verify the horn, wiring, and switch for you.
Is the horn relay controlled by the horn button and or the BCM?
The horn relay can indeed be controlled by either the horn button or the Body Control Module (BCM). click image for an enlarged view Neither hom shown in the wiring diagram will work when the horn button is pressed.
How much does it cost to fix a horn relay?
The average cost for a Horn Relay Replacement is between $70 and $90. Labor costs are estimated between $42 and $61 while parts are typically priced around $28. This range does not include taxes and fees, and does not factor in your unique location. Related repairs may also be needed.
Can I connect a horn without a relay?
If the new horn has a higher current rating, then you need to add the relay. Typically power horns are rated at 5A. So if you are installing a power horn you must add the relay as well.
Does the horn have a relay?
The relay is triggered to send power to the horn either by a switch or by the body control module (BCM) that receives switch input and responds. Some horn relay circuits are built into the module and there is no separate relay. Electricity follows one path in the circuit, and the horn button is a normally open switch.
