* A constant 12V power wire: This wire provides power to the radio's memory even when the ignition is off. This is often red or red/white.
* A switched 12V power wire: This wire only provides power when the ignition is turned on. This is often yellow or yellow/black.
* A ground wire: This wire completes the circuit and is usually black.
To find the correct wires:
1. Consult your vehicle's wiring diagram: This is the most reliable method. You can often find a wiring diagram online (search for "1998 Chevy Silverado radio wiring diagram") or in a repair manual specific to your truck.
2. Use a multimeter: With the ignition off, check each wire for voltage relative to a good ground point. The constant power wire will show 12V. The switched power wire will show 0V with the ignition off and 12V with the ignition on. The ground wire will always show near 0V.
3. Look at the radio harness connector: The wires are often color-coded, and you might find a legend printed on the connector itself or in the vehicle's documentation.
Caution: Always disconnect the negative battery terminal before working on the vehicle's electrical system. Improper wiring can damage your radio or vehicle's electrical system. If you are not comfortable working with car wiring, it is best to seek professional help.
