* Neutral Safety Switch (NSS): This is the most probable cause. The NSS prevents the starter from engaging unless the transmission is in Park or Neutral. A faulty NSS won't allow the car to start, and it's also often responsible for the gear selector sticking. This switch is relatively inexpensive and easy to replace.
* Ignition Switch: A failing ignition switch might not be sending power to the necessary components to start the engine. While less likely to cause the stuck-in-park issue on its own, it can contribute to the overall problem.
* Battery/Wiring: Although it cranks, a weak battery or corroded/loose battery cables could prevent enough power from reaching the starter and other critical systems. Check the battery terminals for corrosion. A completely dead battery won't even crank, though.
* Starter Motor: It *could* be a failing starter motor, even though it's cranking. A weak starter might not provide enough power to turn the engine over fast enough to ignite the fuel/air mixture. However, this is less likely if it's turning over consistently but just not starting.
* Immobilizer System (if equipped): Some 1997 Blazers might have an immobilizer system. If the system detects a problem with the key, it could prevent the engine from starting. Try a spare key if you have one.
* Fuel Pump Relay/Fuel Pump: Check if the fuel pump is activating when the key is turned to the "ON" position (but not cranking). You should hear a brief hum from the fuel pump. A faulty relay or fuel pump itself could be preventing fuel from reaching the engine.
Troubleshooting Steps:
1. Check the Battery and Cables: Clean the battery terminals thoroughly. Have the battery tested at an auto parts store to ensure it's holding a charge.
2. Neutral Safety Switch: This should be your primary focus. Inspect the switch (often located on the transmission) and try wiggling the gear selector while someone attempts to start the vehicle.
3. Ignition Switch: If the NSS seems fine, you may need to test the ignition switch itself, or have it tested at an auto parts store that performs this service.
4. Test for power at the fuel pump: See if the pump activates. If not, there's an issue with its relay, wiring or the pump itself.
5. Check all fuses and relays: This is good practice for any starting issue.
6. Check for any diagnostic trouble codes (DTCs): Even though the dash lights aren't working, you might be able to use an OBD-II scanner to retrieve codes (if your vehicle supports it).
Since your dash lights aren't working, it's possible a more significant electrical issue is present. This makes a thorough check of the battery, cables, and fuses even more important. If you're not comfortable working on your vehicle's electrical system, take it to a qualified mechanic. The NSS is a likely culprit given the stuck-in-park aspect, but several other factors are at play here.
