* Blown fuse: The most common cause. Check your owner's manual to locate the horn fuse and replace it if it's blown.
* Relays: Horn operation often involves a relay. A faulty relay can prevent one or both horns from working. You might need to test the relay (often located in the underhood fuse box) or replace it.
* Wiring: A break or short in the wiring harness leading to one of the horns is a possibility. This requires tracing the wiring to find the problem. Corrosion at connectors is a common culprit.
* Horn itself: One of the horns might be faulty. They can simply fail due to age or corrosion. Testing each horn directly with a 12V source (carefully!) can determine if it's the horn itself.
* Steering wheel control: While less likely, a problem with the steering wheel controls (the horn button itself or the wiring related to it) could prevent one horn from activating.
Troubleshooting steps:
1. Check the fuse first. This is the easiest and cheapest solution.
2. Inspect the horns visually. Look for any obvious damage or corrosion.
3. Test the horns (carefully) with a 12V source. This will isolate whether the horn is faulty or the problem lies elsewhere.
4. Check the wiring for breaks, corrosion, or loose connections. This may require some electrical diagnostic skills or a mechanic.
5. Test the relay (if you can locate it). Again, this might require some electrical knowledge or a mechanic.
If you're not comfortable working with car electrical systems, it's best to take your Impala to a qualified mechanic for diagnosis and repair. Improperly working with car electrical systems can be dangerous.
