* Battery: This is the most common cause. A completely dead battery will provide no power to the starter. Check the battery voltage with a multimeter. It should read around 12.6V when fully charged. If it's significantly lower, charge or replace the battery.
* Battery Cables: Corroded or loose battery cables can prevent sufficient current flow. Inspect the cables at both the battery terminals and the starter connection. Clean any corrosion with a wire brush and ensure tight connections.
* Ignition Switch: The ignition switch might be faulty and not sending power to the starter solenoid. This is less common but possible.
* Neutral Safety Switch (NSS): This switch prevents starting unless the transmission is in park or neutral. A faulty NSS will prevent the starter from engaging. Testing this switch requires a multimeter to check for continuity in the appropriate gear positions.
* Starter Solenoid: While you're not hearing a click, a completely failed solenoid might not make any noise at all. It's the part that bridges the power from the battery to the starter motor.
* Wiring Issues: A break or short in the wiring between the battery, ignition switch, NSS, and starter could interrupt the circuit. This requires careful inspection of the wiring harness.
* Fuse or Circuit Breaker: Check the fuses and any circuit breakers related to the ignition system. A blown fuse will prevent power from reaching the starter.
Troubleshooting Steps:
1. Check the Battery: This is the first and easiest step. Use a multimeter to measure voltage.
2. Inspect Battery Cables: Look for corrosion and loose connections. Clean and tighten them.
3. Check Fuses and Circuit Breakers: Consult your owner's manual to locate the relevant fuses and breakers.
4. Test the Neutral Safety Switch (NSS): This requires a multimeter and some knowledge of automotive electrical systems. Look up a tutorial specific to your year and model of S10.
5. Try Jumping the Starter (with caution): If you have another car and jumper cables, carefully attempt to jump-start the Blazer. If it still doesn't crank, it's less likely to be the battery. *Be extremely careful with jumper cables to avoid sparks and short circuits.*
6. Check for Power at the Starter Solenoid: With the ignition on, use a multimeter to check for power at the large power cable connected to the solenoid. If there is no power, the problem lies before the solenoid (battery, cables, ignition switch, NSS, wiring).
If you're not comfortable working with car electrical systems, it's best to take your Blazer to a qualified mechanic. Attempting repairs without proper knowledge can be dangerous.
