How do you fix a 1999 Isuzu rodeo horn that stays on?

1. Check the horn relay. The horn relay is a small, electrical switch device located in the engine bay. It's responsible for sending power to the horn when you press the horn button. If the relay is faulty, it can cause the horn to stay on even when you're not pressing the button. To check the relay, simply remove it from its socket and inspect it for any signs of damage. If the relay is damaged, replace it with a new one.

2. Check the horn switch. The horn switch is the button that you press to sound the horn. If the switch is faulty, it can cause the horn to stay on even when you're not pressing it. To check the switch, simply press it and see if the horn sounds. If the horn doesn't sound, then the switch is faulty and needs to be replaced.

3. Check the horn wiring. The horn wiring is the electrical wires that connect the horn relay, horn switch, and horn. If any of the wires are damaged, it can cause the horn to stay on. To check the wiring, simply inspect the wires for any signs of damage. If you find any damaged wires, repair them or replace them with new wires.

4. Check the horn. If you've checked all of the above components and the horn is still staying on, then the problem may be with the horn itself. To check the horn, simply remove it from the vehicle and test it by connecting it directly to a 12-volt power source. If the horn doesn't sound, then it's faulty and needs to be replaced.