Simple Checks (Before Anything Else):
* Battery: This is the most common cause of no-start issues. Test the battery voltage with a multimeter. It should read around 12.6 volts when fully charged. If it's low, charge it or replace it.
* Battery Cables: Inspect the battery cables for corrosion, loose connections, or damage. Clean the terminals with a wire brush and reconnect them securely.
* Wiring: A faulty connection during the ignition switch replacement is highly probable. Double-check *all* the wiring to the new switch, ensuring each wire is securely connected to the correct terminal. A mis-wired ignition switch can cause a no-start condition or even damage the vehicle's electrical system. Refer to a wiring diagram.
* Ignition Switch Itself: While unlikely if you're sure you purchased a quality replacement, it's possible the *new* ignition switch is faulty. Contact the seller or supplier.
* Key: Make sure you're using the correct key. A bad key will not engage the switch properly.
* Neutral Safety Switch (Automatic Transmission): If you have an automatic transmission, the neutral safety switch prevents the engine from starting unless the transmission is in park or neutral. Check that the transmission is in park or neutral and that the switch is functioning correctly. This is a common problem on S-10s.
* Steering Column Lock: Make sure the steering wheel isn't locked. Sometimes a slightly turned wheel will engage the lock and prevent starting.
More Complex Issues:
* Immobilizer System (If Equipped): Some S-10s had an immobilizer system that prevents starting if the correct key isn't recognized. Try a different key if possible.
* Starter Motor: The starter motor might be faulty, even if unrelated to the ignition switch replacement. It might be seized, have worn brushes, or have a bad solenoid. Testing the starter is recommended.
* Ignition Coil: A weak or failing ignition coil won't provide the necessary spark to ignite the fuel-air mixture.
* Cranking System: This encompasses the starter, battery, cables, and related wiring. A problem here might prevent the engine from even attempting to turn over.
* Fuel System: Check for fuel pressure. A lack of fuel will prevent the engine from starting.
* Computer/ECU Problems: While less likely, a faulty engine control unit (ECU) could be preventing the engine from starting. This would require a professional diagnosis.
* Security System: An aftermarket alarm or security system could be interfering with the starting process.
Troubleshooting Steps:
1. Start with the simple checks. Battery, cables, and wiring are the most common culprits.
2. Use a wiring diagram: Find a wiring diagram specific to your year and model S-10. This is essential for correctly wiring the ignition switch.
3. Test the starter: A mechanic or experienced DIYer can test the starter to ensure it's functioning correctly.
4. Professional Diagnosis: If you've checked all of the above and still can't figure it out, take it to a qualified mechanic. They have the tools and expertise to diagnose more complex electrical problems.
Remember safety first! Disconnect the negative battery terminal before working on the electrical system. If you're not comfortable working on your vehicle's electrical system, it's best to seek professional help.
