1. Gather your tools and materials:
* New radio: Make sure it's compatible with your vehicle's electrical system.
* Wiring harness adapter (highly recommended): This simplifies wiring and avoids potential damage to your vehicle's electrical system. A Metra or Scosche adapter is commonly used for GM vehicles of that era. Look for one specifically designed for a 1991 Chevy S10.
* Screwdrivers (Phillips and possibly flathead): Sizes will depend on your radio and dash.
* Radio removal tools (optional but helpful): These are usually plastic tools that help pry the radio out of the dash without scratching it. You can often find these at auto parts stores.
* Wire strippers/crimpers (if you need to make custom connections): Only needed if you don't use a wiring harness adapter.
* Electrical tape (if needed): To secure any connections.
* Owner's manual (for both the new radio and your truck - if you have it): Helpful for diagrams and specifications.
2. Disconnect the battery: This is crucial for safety to prevent short circuits. Disconnect the negative (-) terminal first.
3. Remove the radio bezel (trim panel): This is the plastic trim surrounding the radio. Usually, it's held in place by clips or screws. Gently pry it loose using your fingers or the radio removal tools, starting at the corners. Be careful not to break any clips.
4. Remove the old radio: Once the bezel is off, you'll see the radio itself. There are usually two metal brackets or screws that hold it in place. Unscrew these and carefully pull the radio out.
5. Disconnect the wiring harness: This is where the wiring harness adapter comes in handy. If you have one:
* Disconnect the factory wiring harness from the old radio.
* Connect the adapter to the factory harness.
* Connect the new radio's harness to the adapter.
If you *don't* have an adapter, you'll need to manually match the wires based on a wiring diagram. You can usually find these online (search for "1991 Chevy S10 radio wiring diagram"). Be extremely careful to match the correct wires to avoid short circuits. This step is significantly more complex and potentially risky without an adapter.
6. Install the new radio:
* Connect the wiring harness to the new radio.
* Slide the radio into the dash opening.
* Secure it with the brackets or screws.
7. Reinstall the bezel: Carefully snap the bezel back into place.
8. Reconnect the battery: Connect the positive (+) terminal first, then the negative (-).
9. Test the new radio: Turn on the ignition and test all functions.
Important Notes:
* Constant power: Make sure the constant power wire is connected correctly. This keeps the radio's memory settings (like presets) even when the vehicle is turned off.
* Illumination wire: This wire controls the radio's backlighting and should be connected to a circuit that's only on when the headlights are on.
* Ground wire: Make sure the ground wire has a good connection to a clean metal surface.
* Antenna: Ensure your antenna is properly connected to the new radio.
If you're uncomfortable with any of these steps, it's best to take your vehicle to a qualified car audio installer. They have the tools and expertise to do the job safely and correctly. Improper wiring can damage your vehicle's electrical system.
