1. Verify Horn Circuit Continuity (Requires a multimeter):
* Locate the horn relay: Even though you couldn't find it where you expected, there *should* be one. Consult your 1991 Pontiac Firebird's wiring diagram. This is crucial. A Haynes or Chilton repair manual for your specific year and model will be invaluable. Online resources might also have diagrams, but accuracy varies.
* Test the horn relay: With the relay removed, use your multimeter to test continuity across the appropriate terminals according to the wiring diagram. A bad relay will usually show an open circuit.
* Test the horn button: With the ignition on, check continuity between the horn button terminals when the button is pressed. A bad button will show an open circuit when pressed. This often requires disconnecting the steering wheel airbag (if equipped, exercise extreme caution and disconnect the battery negative terminal first to prevent airbag deployment), then accessing the horn button wiring.
* Trace the wiring: Using your multimeter, start at the horn itself and trace the wires back toward the steering column. Check for breaks, corrosion, or loose connections along the way. Pay special attention to areas prone to chafing or damage.
2. Check the Ground:
* Horns need a good ground to function. Trace the ground wire from the horn to ensure a solid connection to the car's chassis. Clean any corrosion you find.
3. Consider the Steering Wheel Clock Spring:
* In some vehicles, the clock spring (a spiral cable that allows the steering wheel to turn while maintaining electrical connections) can cause intermittent or complete horn failure. This is less likely but possible. Replacing the clock spring is a more advanced repair.
4. Professional Help:
If you're not comfortable working with car electrical systems, especially if dealing with the airbag, take your Firebird to a qualified mechanic. Improperly working on the airbag system can be dangerous.
Important Safety Notes:
* Disconnect the negative battery terminal before working on any electrical components, especially the airbag system.
* Always consult a wiring diagram specific to your 1991 Pontiac Firebird. Generic diagrams won't be accurate enough.
* Be careful working near the steering wheel airbag. Improper handling can cause accidental deployment.
Finding the wiring diagram is the most important first step. Once you have that, you can systematically test each component in the horn circuit. Remember safety first!
