The car horn honks by itself whenever I turn the steering wheel.
Your clock spring is likely faulty and shorting. The clock spring is the device between the steering wheel, and steering column. It allows you to control the functions of the steering wheel, and turn the steering wheel, while holding all the wires in one place. Removal of the steering wheel and reprogramming will be required in your case, as will the use of a scan tool and other special tools. I recommend having a certified technician, such as one from YourMechanic, run a diagnostic inspection of your car horn issue, and recommend the best path to repair.
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