1. Define the Problem:
* What exactly isn't working? Be specific. Is it the headlights, taillights, radio, power windows, wipers, gauges, the entire electrical system, or something else? The more detail you provide, the better.
* When did it start? Did it happen suddenly, or gradually get worse? Did it coincide with any other event (e.g., a recent repair, a collision, driving through deep water)?
* Are there any patterns? Does it only happen when the engine is running, when it's cold, or under certain conditions?
2. Visual Inspection:
* Battery and Terminals: Check the battery for corrosion on the terminals. Clean them with a wire brush and baking soda and water solution. Make sure the connections are tight. A weak battery can manifest as numerous electrical problems. Test the battery voltage with a multimeter. It should read around 12.6V when not charging.
* Fuses: Check the fuse box(es) (under the hood and usually inside the car, often under the dash). Look for blown fuses (a broken filament). Replace any blown fuses with the correct amperage rating. Do not replace a blown fuse with a higher amperage fuse; this is a fire hazard.
* Wiring: Carefully inspect all visible wiring for any obvious damage – frayed wires, broken insulation, corrosion, or loose connections. Look particularly around areas that may experience vibration or movement.
* Alternator: The alternator charges the battery. A failing alternator can cause similar problems to a weak battery. Visually inspect it for obvious damage and you can have the charging system tested at an auto parts store.
* Grounds: Poor ground connections are a common cause of electrical issues. Check all ground straps (heavy gauge wires connecting various components to the chassis) for corrosion or looseness. Clean them thoroughly if necessary.
3. Testing with a Multimeter:
A multimeter is an essential tool for electrical diagnostics. You'll need to know how to use it to measure voltage and continuity.
* Voltage Testing: Check the voltage at various points in the circuit. Compare your readings to the values specified in a wiring diagram (available online or from a repair manual). Low voltage often indicates a problem in the wiring or a faulty component.
* Continuity Testing: Use this function to check for broken wires or bad connections. Disconnect the wire from the circuit and test for continuity between the two ends. A continuous circuit should register 0 ohms or very low resistance.
4. Wiring Diagrams:
Obtain a wiring diagram for your specific 1991 Chevy Cavalier. These diagrams show how the electrical components are connected and can be invaluable for tracing circuits. You can find them online through forums dedicated to classic Chevy vehicles, or in a repair manual.
5. Component Testing:
If you've narrowed the problem to a specific component (e.g., a faulty switch, a bad relay), you may need to test the component itself. This often requires more advanced diagnostic tools or expertise.
6. Seek Professional Help:
If you're not comfortable working with car electricity, or if you've tried the above steps and are still unable to identify the problem, it's best to take your car to a qualified mechanic. Incorrectly working with car electrical systems can be dangerous.
Important Safety Precautions:
* Disconnect the battery negative terminal before working on any electrical system in your car to avoid shorts or shocks.
* Never work on a car's electrical system while the engine is running.
* Be aware of sharp edges and moving parts.
* Use appropriate safety glasses and gloves.
Troubleshooting electrical problems takes patience and a systematic approach. By following these steps and using the right tools, you stand a much better chance of identifying and fixing the issue. Remember safety first!
