1. Check the Obvious:
* Battery: Test the battery voltage. A low voltage reading (below 12.2V) means it needs charging or replacing. Even if it starts, a weak battery can cause cranking issues. Have it load tested at an auto parts store for a definitive answer.
* Battery Cables: Inspect the battery cables (positive and negative) for corrosion, looseness, or damage. Clean the terminals with a wire brush and baking soda and water, ensuring a tight connection.
* Starter Relay: Many older vehicles have a separate starter relay. Locate it (usually near the battery or under the hood) and check for proper function. You might hear a clicking sound from this relay if it's the problem. Try tapping it gently with a wrench—this is a temporary fix and doesn't address the root cause, but it can help diagnose the problem.
2. Focus on the Starter:
* Starter Motor: The starter motor itself might be faulty. This often manifests as a clicking sound when you turn the key, or complete silence. A mechanic can test the starter directly.
* Starter Solenoid: This is a part of the starter motor. A bad solenoid prevents the starter motor from engaging. Again, often leads to clicking noises.
3. Ignition System:
* Ignition Switch: While you have power, a faulty ignition switch might not be sending the correct signal to the starter.
* Neutral Safety Switch (Manual Transmission): This switch prevents the engine from starting unless the transmission is in neutral. Make absolutely sure your transmission is in neutral. If it is, this switch may need replacing.
* Clutch Safety Switch (Manual Transmission): Some vehicles require the clutch pedal to be fully depressed before the starter engages. Make sure the clutch pedal is fully depressed. If it is, this switch may need replacing.
* Wiring: Check all wiring related to the starter, ignition, and neutral/clutch safety switches for damage, breaks, or loose connections.
4. Less Likely but Possible:
* Immobilizer System (if equipped): Some 1986 models might have a rudimentary anti-theft system. Though less common on that model year, it's worth considering if nothing else works.
* Other Electrical Problems: A broader electrical issue could be causing the problem. This is less likely if you have power to other systems in the truck.
What to Do:
1. Start with the simple checks (battery, cables). This is the easiest and cheapest approach.
2. Listen carefully for clicking sounds. This will help pinpoint the problem area.
3. If you have basic electrical knowledge, use a multimeter to test the voltage at various points in the starting circuit. This will help you isolate the problem.
4. If you're not comfortable working on your vehicle's electrical system, take it to a mechanic. Improper diagnosis or repair can lead to further damage.
Remember safety first! Disconnect the negative battery terminal before working on any electrical components. Always consult your vehicle's repair manual for detailed diagrams and procedures.
