A blown fuse is a common reason that car radios stop working. It is easy to replace a blown fuse for a car radio. Aftermarket car radios may have an additional fuse.
Turn off the vehicle. Locate the main fuse box. Most cars' fuse boxes are under the dashboard just to the left of the steering wheel. If the fuse box is there, remove the plastic cover. Different car models have different covers, so you may need to remove a holding screw before popping the cover off.
Locate a fuse box that isn't under the dashboard by checking under the bonnet of the car. Fuse boxes kept in the engine compartment are usually black. The final place to check for a fuse box if it is not in one of the other locations is in or around the glove compartment. Again, a cover may be held in place with a screw. Your owner's manual can guide you on finding your car's fuse box or boxes and removing the covers.
Look at the diagram on the inside of the fuse box's cover. This diagram has numbers that correspond with different fuses for different electrical components. Look for the words "radio" or "audio system" and take note of the associated number. Locate the fuse that is in the numbered slot and gently pull the fuse out. The diagram may also be found in the car manual.
Determine if the fuse is blown by looking through the clear plastic casing. A blown fuse will have a blackened look, or the metal connection inside will be broken in half. A fuse looks like a small, see-through plastic square and has two small metal prongs sticking out of it. Most fuses are smaller than 1 inch by 1 inch.
Take the blown fuse to an electronics store or a car-parts store. Ask a store employee to help locate a new fuse that will fit as a replacement. Be prepared to give information such as the car make and model.
Push the new fuse into the empty slot in the fuse box, making sure that it is in the same direction as the other fuses. It should slide in with a tight fit.
Replace the fuse-box cover. Turn the car's ignition on and test the radio. If the blown fuse was causing the problem, the radio should work.
Complete the above steps before removing the car radio. If you have a car radio that you installed or had installed after you purchased the car, the radio may have its own built-in fuse. If the radio does not work after replacing the fuse in the main fuse box, check the radio's built-in fuse.
Disconnect the car battery under the bonnet by disconnecting the cable from the negative terminal (the black cable) of the battery. If the stereo has an antitheft device, get the code before disconnecting the battery.
Remove the dash area around the car radio. It may pop off or may be held with screws and clips. Unscrew the holding screws and gently pull off the dash moulding around the radio. Check for any clips holding the panel in place while removing. The trim panel may be one large plastic piece, and removing it may uncover a large portion of the centre dash area.
Unscrew the four screws on each corner of the car stereo. Slide out the car radio, being careful not to disconnect the connected wires and cables.
Locate the fuse on the back of the car radio. This fuse may look similar to the fuses in the main fuse box of the car. Slide the fuse out and inspect it for darkened areas or broken connections.
Take the blown fuse to a car-parts store or electronics store to find a replacement fuse. Place the new fuse into the car radio.
Slide the car radio back into the dash opening. Replace the corner screws followed by the dash trim panels. Put any screws and clips back into place.
Reconnect the car battery. Turn the car on, and if the blown fuse was the problem, the radio should work.
Check the main fuse box of the car first. Only if that fuse replacement doesn't fix the issue, go on to the radio removal.
Always disconnect the negative terminal cable from the battery before servicing the electrical components of the car. If you are unsure of whether the car radio contains its own fuse, consult the manual or take the car to an audio installation shop.