1. Battery and Connections:
* Check the Battery: Test the battery voltage with a multimeter. It should read around 12.6 volts when fully charged. A low voltage will prevent the car from starting and affect the power to the gauges.
* Inspect Battery Terminals and Cables: Look for corrosion, looseness, or damage to the battery terminals and cables. Clean any corrosion with a wire brush and baking soda solution, and ensure connections are tight.
* Check the Ground Straps: A poor ground connection can also cause similar issues. Locate the main ground straps from the engine block and battery to the chassis, and check for corrosion or looseness.
2. Ignition Switch:
* Faulty Ignition Switch: A malfunctioning ignition switch can fail to send power to the rest of the system when the key is turned. This is a likely culprit given the lack of power to the gauges. Testing this requires a wiring diagram and multimeter to check for power at the switch and outgoing circuits.
3. Wiring and Fuses:
* Check Fuses: Inspect the fuses in the fuse box (usually under the hood and/or inside the car). Look for blown fuses, especially those related to ignition, power distribution, and the instrument panel. Replace any blown fuses *after* addressing any underlying short circuit. A blown fuse is a symptom, not the root cause.
* Wiring Harness Issues: Look for any damaged or corroded wiring, particularly in the area of the ignition switch and the main power distribution points. This could involve breaks in the harness or short circuits.
4. Neutral Safety Switch (Automatic Transmission):
* Automatic Transmission Only: If it's an automatic, a faulty neutral safety switch prevents the starter from engaging unless the transmission is in park or neutral. This switch won't cause the gauge issue, but it prevents starting. Check that the car is in park or neutral.
5. Other less likely, but possible causes:
* Alternator: While the alternator charges the battery when the engine is running, a completely failed alternator may prevent the car from even cranking (though your symptoms suggest it's cranking ok).
* Starter Relay: Could be sticking or failing, preventing sufficient power to the starter motor, but it's less likely given the gauge issue.
Troubleshooting Steps:
1. Start with the easiest checks: Battery voltage, terminal condition, and fuses.
2. Visual inspection: Check wiring for damage or corrosion.
3. Use a multimeter: Test voltage at various points in the circuit, following a wiring diagram (available online or from a repair manual) to track power flow. This is crucial to diagnose the ignition switch and any wiring faults.
4. Consider professional help: If you're not comfortable working with car electrics, it's best to take it to a mechanic. Diagnosing electrical problems can be complex.
Important Note: The lack of power to the gauges is a significant clue. It points away from a simple starter or ignition coil issue and towards a more fundamental power distribution problem, likely in the ignition switch, wiring, or main power circuits. Be careful when working with car electricity to avoid short circuits.
