The power supply to the battery is not adequate due to a poor battery terminal connection/ground. Clean the terminals and ensure that the connections are tight.
2. Faulty Relay or Fuse
A faulty relay or fuse can prevent the flow of power from the battery to the electrical components. Check these components and replace them if necessary.
3. Alternator Issues
Although you mentioned the alternator tested good, it's still worth taking another look. A failing alternator can cause the power to die while driving.
4. Voltage Regulator Problems
A malfunctioning voltage regulator might not be properly managing the charging system. This can lead to power loss.
5. Battery Not Holding a Charge
A battery that doesn't hold a charge can cause the power to die. Have your battery tested to determine its health.
6. Grounding Issues
A bad grounding connection between the battery and chassis can cause the electrical components to malfunction and lose power.
7. Damaged Wiring or Harness
Damaged, corroded, or loose wiring can affect power supply. Inspect the wiring and replace or repair any damaged sections.
8. Faulty Ignition Switch
A faulty ignition switch might not allow the electrical system to be turned on.
9. Overloaded Electrical System
If you have added aftermarket electrical accessories or devices that draw excessive power, it can overload the electrical system and lead to power loss.
10. Computer/Module Problems
In some cases, a malfunctioning computer or control module can disrupt power distribution.
11. Short Circuits
A short circuit can cause a power drain, leading to power loss. Look for any exposed or frayed wires that might be causing the short.
