1. Battery and Connections:
* Battery Voltage: Check the battery voltage with a multimeter. It should be around 12.6 volts when fully charged. A low voltage will prevent the starter from engaging.
* Battery Cables: Inspect the battery cables (positive and negative) for corrosion, looseness, or damage. Clean the terminals with a wire brush and baking soda solution if necessary, and ensure they're securely fastened. Pay close attention to the connections at both the battery and the starter.
2. Starter Solenoid:
* Solenoid Click: When you turn the key, do you hear a single click? This often indicates a problem with the solenoid, which is the electrical switch that engages the starter motor. A weak click might mean a low battery or a bad solenoid. A loud click might mean the solenoid is working, but the starter motor itself is faulty.
* Solenoid Testing (Advanced): You can test the solenoid with a multimeter by checking for continuity between the terminals. This requires some electrical knowledge and the appropriate safety precautions. There are many online tutorials showing how to test a starter solenoid.
3. Starter Motor:
* Starter Motor Itself: If you've ruled out battery and solenoid issues, the starter motor itself might be faulty. It could be worn out, have internal short circuits, or have a seized gear. This usually requires replacing the starter.
* Starter Motor Removal and Inspection (Advanced): Removing and inspecting the starter is more involved and typically requires mechanical knowledge. You'll need tools and potentially a repair manual. Look for obvious signs of damage or seizing.
4. Neutral Safety Switch:
* Transmission in Park/Neutral: Ensure your transmission is firmly in Park (P) or Neutral (N). A faulty neutral safety switch prevents the starter from engaging unless the transmission is in the correct position. This switch can be tested with a multimeter.
5. Ignition Switch:
* Ignition Switch Failure: A failing ignition switch might not be sending the correct signal to the starter. This is less common but possible.
6. Other Possible Issues:
* Flywheel Teeth: Worn or damaged teeth on the flywheel (the part the starter engages) can prevent the crankshaft from turning. This requires inspecting the flywheel, often requiring removal of the transmission.
* Broken Starter Bendix Gear: The bendix gear is the part of the starter that meshes with the flywheel. If it's broken or jammed, it will not turn the crankshaft.
Recommendations:
* Start with the simple checks: Battery voltage and cable connections are the easiest and most common causes.
* Use a multimeter: This will help diagnose electrical problems accurately.
* Consult a repair manual: A repair manual specific to your 1992 Chevy Blazer will provide detailed diagrams and instructions.
* Seek professional help: If you're uncomfortable working with car electrical systems or mechanics, take it to a qualified mechanic. Incorrect diagnosis can lead to further damage.
Remember safety first! Disconnect the negative battery cable before working on any electrical components. Working on a car's electrical or mechanical systems can be dangerous if you are not familiar with the proper procedures.
