1. Battery Cables: Before anything else, carefully inspect the positive (+) and negative (-) battery cables. Make sure they're securely connected to both the battery and the vehicle's terminals. Loose connections can cause arcing, which creates that "pop" sound and can blow fuses or damage components. Look for any signs of corrosion, melting, or damage to the cables themselves. Clean the terminals thoroughly with a wire brush if necessary.
2. Fuse Box(es): The Chevy Express likely has multiple fuse boxes. Locate them (usually under the hood and sometimes inside the cabin, often under the dash). Check all fuses, particularly those related to the starting system (often labeled "ignition," "starter," or similar). Use a test light or multimeter to verify if a fuse is blown (no continuity). Replace any blown fuses with fuses of the *exact same amperage*. Don't just stick in a higher amperage fuse; that's a fire hazard.
3. Positive Battery Cable Fuse: Some vehicles have a large fuse inline with the positive battery cable, often close to the battery itself. This fuse is sometimes a mega-fuse or a fusible link. Inspect this carefully. It might be hidden in a protective plastic cover.
4. Alternator: The "pop" sound *could* indicate a problem with the alternator. A faulty alternator could draw excessive current, blowing a fuse or even damaging other components. This is less likely to be the *direct* cause of the immediate power loss, but it's worth investigating later if other fuses aren't the problem.
Important Considerations:
* Reverse Polarity: Did you accidentally connect the positive and negative battery cables incorrectly? This is a serious mistake that can cause significant damage. Check the battery connections very carefully. If you think you might have done this, have a qualified mechanic examine the vehicle.
* Ground Connections: Poor ground connections can also cause strange electrical problems. Check all ground straps (heavy gauge wires attached to the chassis) for corrosion or looseness.
* Wiring Harness Damage: While less likely, the "pop" could have indicated damage to a wire in the vehicle's wiring harness, possibly due to a short circuit. This would require a more thorough inspection.
If you're not comfortable working with car electrical systems, take your vehicle to a qualified mechanic. Attempting to diagnose and repair electrical issues without proper knowledge can lead to further damage and potential injury. They have the tools and expertise to properly diagnose the problem and get your van running safely.
