Safety First: Disconnect the negative battery cable before performing any testing. This prevents accidental shorts and shocks.
1. Battery and Connections:
* Voltage Check: Use a multimeter to check the battery voltage. It should read around 12.6 volts when fully charged. Less than 12 volts indicates a weak or dead battery.
* Cable Connections: Inspect the battery terminals and cable connections for corrosion, looseness, or damage. Clean them with a wire brush if necessary and tighten connections. A loose connection can cause clicking.
* Cable Test: While someone turns the key to the start position, check for voltage drop across the battery cables. A significant voltage drop indicates a problem in the cables themselves.
2. Starter Motor:
* The Clicking Source: Is the clicking coming directly from the starter motor (located on the engine block, usually near the flywheel)? This strongly suggests a starter motor issue.
* Starter Solenoid: The clicking might be the starter solenoid engaging and disengaging, but not providing enough power to crank the engine. This can be due to a bad solenoid, low battery voltage, or a faulty connection to the solenoid. You might even be able to tap the solenoid gently with a wrench (while the key is *off*) to see if that helps. *Use caution and don't hit it hard*.
* Starter Motor Failure: The starter motor itself could be failing internally (worn brushes, damaged windings).
3. Ignition System:
* Ignition Switch: A faulty ignition switch can prevent the starter from receiving power. This is less likely to cause a *clicking* noise, but it's possible.
* Neutral Safety Switch (Automatic Transmission): If you have an automatic transmission, this switch prevents starting unless the gear selector is in Park or Neutral. A faulty switch can prevent starting.
* Other Ignition Components: While less likely to cause a distinct clicking, issues with the ignition coil, distributor (if equipped), or ignition wires can prevent starting, but may manifest as other symptoms (like no spark).
4. Other Possibilities (less likely with a clicking sound):
* Low Fuel: While unlikely to cause a clicking noise, ensure you have enough fuel.
* Security System: Some vehicles have aftermarket security systems that could prevent starting.
Troubleshooting Steps:
1. Battery Test: Start with the battery voltage check. This is the quickest and easiest test.
2. Connection Inspection: Thoroughly inspect all battery cables and connections.
3. Starter Solenoid Inspection: If you hear the click from the starter solenoid area, check the connections there. Consider tapping it lightly (while the key is OFF).
4. Jump Start (Caution): If the battery seems okay and the clicking persists, try a jump start from another vehicle. If it starts, the problem is likely the battery or charging system. Don't jump start for too long if it doesn't start immediately.
5. Professional Help: If you can't identify the problem after these steps, it's time to take it to a mechanic or auto electrician. They have the tools and expertise to diagnose more complex issues.
Remember, working on car electrical systems can be dangerous. If you are not comfortable working with electricity, it is best to seek professional help. A 1987 vehicle might have some safety concerns, so exercise caution.
