Contenu
- Tool-Free Test
- Step 1
- Step 2
- Specialized Test
- Step 1
- Step 2
- Step 3
- Step 4
- Step 5
- Step 6
- Step 7
- Items you will need
One reason a vehicles horn may not work is a failed horn relay. Testing a vehicles horn relay is the place to begin when troubleshooting a horn that fails to honk. You can sometimes test a horn relay easily and without tools. A second, more exact method requires special instruments and a power source.
Tool-Free Test
Step 1
Determine where the relay box is mounted by referring to the owners manual. Locate the horn relay inside the relay box.
Step 2
Pull the horn relay from the relay box. In the same relay box, find a relay of equal size. Pull that relay from its seat and plug it in the horn relays seat. If a comparable relay to the horn relay cannot be found, this method of testing can not be used.
Turn the cars ignition to the "On" position. Attempt to honk the horn. If the car honks, the relay originally seated in the horn relay seat does not function properly.
Specialized Test
Step 1
Find the relay diagram illustrated in the vehicle owners manual and learn where the relay box is mounted in the car. Find the relay box in the car.
Step 2
Pull the horn relay from its seat in the relay box.
Step 3
Adjust the multimeter to the resistance setting.
Step 4
Identify the ground, voltage, battery and load prongs on the relay.
Step 5
Fasten one of the multimeters clamps to the load prong that goes to the horn and one to the battery prong.
Step 6
Connect the ground terminal from the cars battery to the ground prong on the relay with a double jumper wire. Connect the jumpers other wire to the positive terminal on the cars battery.
Step 7
Touch the other end of the jumper wire connected to the car batterys positive terminal to the relays voltage or input prong.
Read the multimeter, check for continuity and listen to the relay for a clicking sound. Continuity and clicking indicate a good relay. No clicking and no continuity are symptoms of a failed relay.
Items you will need
- 12-volt battery
- Multimeter
- Double jumper wire
