How to Fix a Car Amplifier

By Rhonda Campbell


Car amplifiers are available in two, four or five channels and in watt size from 50 to 500. Amplifiers "amp up" or boost the sound of your car's stereo system. They can work incorrectly or stop working altogether for several reasons. If you installed the equipment yourself it might be easier for you to locate and fix the problem. If the dealer or someone else installed the equipment for you, it may take a little longer to locate and resolve problems.

Step 1

Check the amplifier hook up. If the amplifier is secured to an unclean or non-metal surface, remove the wires and unscrew the amplifier. Next, secure the amplifier to a clean, metal base like a flat surface beneath a car seat or at the bottom of your car's trunk. Make sure that the space is free of rust and debris. Attach the stereo system remote turn-on lead wire to the back of the remote terminal on the amplifier. If the signal transfer is weak, use crimp-on space or ring terminals to connect the remote lead wire to the amplifier. You can also replace narrow hook up wires with thicker ones. Thicker wires, about 18 gauge, give the amplifier more current output.

Step 2

Cool the system. Turn the amplifier off after several hours of usage when on long trips. Install a new fuse in the amplifier to prevent over heating or shortages. You can also add cooling fans like the ones used in a personal computer to your amplifier if your system has been over heating. Three to five inch fans are fine. Connect the fan to your car's electrical system. Add a power switch that runs from the fan to the amplifier. If you have a large amplifier, adding additional fans might improve your car's sound significantly. Also remove any large objects away from your amplifier as the more clear space there is around the equipment, the less likely the system is to over heat.

Step 3

Check the speaker wires. Replace worn speaker wires. Make sure that existing wires are installed high enough so they do not touch the amplifier's metal base. Untangle bunched wires and check that wires are not being flattened by you or a passenger if you installed your amplifier beneath a car seat.

Step 4

Test the output transistors. Turn the amplifier off. Use a multi-meter set at ohms. Insert the multi-meter probes in the amplifier's ohms sockets. The sockets might be labeled COM. Turn the multi-meter to check the output transistor terminal resistance measurements (see Resources). For terminals that show a reading above zero, visit your nearby electronics or auto store and replace the output transistors.