Buy a computer-safe test light for auto trouble-shooting
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Computer-safe test light
This LED test light plugs into the cigarette lighter.
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Incandescent test light
The old style test light can damage auto electronics.
Using a test light to check for circuit voltage is a
tried-and-true diagnostic method. But if you probe a
computerized circuit with your old incandescent test light, you can fry some sensitive and expensive electronics. Since almost every circuit in a late-model car is controlled by a computer, it's best to say goodbye to your old test light and invest in a computer-safe test light. These don't pull any power from the tested circuit. Instead, they plug into the cigarette lighter. A red LED means the circuit has power. A green LED means the circuit is connected