A non-functional car horn is a traffic violation in UAE and an immediate fail on the RTA periodic test. If your horn has stopped working, the fault can usually be traced to one of five components. This guide walks through the diagnostic process in order of likelihood and cost.
Step 1: Check the Fuse
The horn fuse is the first and cheapest thing to check. Locate the fuse box (usually under the bonnet or inside the driver compartment). The owner manual shows which fuse covers the horn. Pull the horn fuse and inspect it. A blown fuse costs under AED 5 to replace. If the new fuse blows immediately, there is a short circuit in the horn wiring that needs workshop diagnosis.
Step 2: Check the Horn Relay
If the fuse is intact, the horn relay is the next likely cause. The relay is in the fuse/relay box, typically labelled on the lid. Swap it with an identical relay from another circuit (such as the fog light relay if they match the part number). If the horn now works, replace the relay. Cost: AED 20 to AED 60.
Step 3: Test the Horn Unit
The horn unit is mounted behind the front bumper or grille. Connect it directly to the battery with jump leads to test it in isolation. If it sounds, the problem is in the wiring or switch circuit. If it does not sound, the horn unit has failed. Horn replacement: AED 60 to AED 200.
Step 4: Clock Spring Fault
If the horn worked until recently and stopped suddenly, often accompanied by the airbag warning light or loss of steering wheel controls, the clock spring has failed. The clock spring is the coiled ribbon cable inside the steering column that carries the horn signal. This is the most common cause of horn failure on vehicles with steering wheel-mounted controls. Clock spring replacement: AED 200 to AED 600.
Step 5: Horn Button or Switch Contacts
On older UAE vehicles without a clock spring, the horn button contacts inside the steering wheel may be worn or corroded. This is diagnosed by testing voltage at the horn unit while pressing the button. Contact repair or switch replacement: AED 100 to AED 300.