Common Symptoms of a Bad Ignition Switch:
* Intermittent Starting: This is a major clue. The engine might crank sometimes but not others, even with a good battery and starter. The key might feel loose or not turn smoothly in the ignition.
* Electrical Problems: Problems with accessories like headlights, wipers, radio, or power windows could indicate a faulty ignition switch, especially if these issues are intermittent and related to the key's position.
* No Power at All: In some cases, a completely failed ignition switch might prevent any power from reaching the vehicle's electrical system, meaning nothing works at all.
* Key Stuck in Ignition: The key might become stuck in the "ON" or "ACC" position.
* Accessory Issues: Some accessories might work only when the key is in a particular position, or not at all, regardless of the key position.
Testing the Ignition Switch:
Testing the ignition switch directly requires some electrical knowledge and tools (multimeter). It's generally easier to test other components first to rule them out:
1. Battery and Cables: Ensure your battery is charged and the battery cables are clean, tight, and properly connected. A weak battery or loose cables can mimic ignition switch problems.
2. Starter: If the engine cranks slowly or not at all, the starter motor might be the problem. Have it tested by a mechanic or auto parts store.
3. Neutral Safety Switch (Automatic Transmission): On automatics, make sure the transmission is in Park. A faulty neutral safety switch prevents starting. You can usually check this by measuring continuity across the switch terminals (refer to a wiring diagram).
4. Ignition Switch Wiring: Visually inspect the wiring harness connected to the ignition switch for damage, corrosion, or loose connections.
If the above tests don't reveal the problem:
The ignition switch is located under the steering column and requires some disassembly to access. This is NOT a beginner-level repair. You'll need to:
* Consult a wiring diagram: A wiring diagram specific to your 1991 Ford Bronco is essential to understand the switch's circuitry and to properly test it with a multimeter. You can find these online or in a repair manual.
* Use a Multimeter: With the wiring diagram, you can use a multimeter to test for voltage and continuity at various points in the ignition circuit while turning the key. This will help isolate the problem to the switch itself.
Important Considerations:
* Safety: Disconnect the battery's negative terminal before working on any electrical components.
* Complexity: Replacing the ignition switch can be more involved than it seems, often requiring removal of the steering column cover, steering wheel, and other parts.
* Professional Help: If you're not comfortable with automotive electrical work, it's best to take your Bronco to a qualified mechanic to diagnose and repair the problem. Improperly diagnosing or repairing an ignition switch can cause more damage.
By systematically checking these areas, you can increase your chances of correctly identifying whether the ignition switch is indeed at fault. Remember safety first!
