Many car stereo's today accept many auxiliary components from an MP3 player, USB flash drive, a computer, and even a car microphone. However, the stereo must have some sort of auxiliary port to accept the jack from the incoming devices. Older factory stereos do not have this type of auxiliary jack for the use of a car microphone or other devices. To wire in a car microphone you will need to do it first by adding an auxiliary jack to the stereo.
Step 1: Determine Location for Auxiliary Jack
Most of the time the auxiliary jack is located on the face of the stereo itself. When you add one you will not be able to do that unless you carefully drill into the face of your stereo. Finding a new location will be more beneficial. Most of the time the best places are in the glove compartment where it is out of the way, or under the dash. For this installation we are going to go through the glove compartment.
Step 2: Disconnect Battery
Using a Philips screwdriver, or wrench, remove the battery cables from the battery posts. This will ensure against any possible mistake or accidentally touching a live wire.
Step 3: Remove Dashboard Panel
Using a panel remover tool, or a flat blade screwdriver you will need to remove the dashboard trim. This should be done carefully so as not to break the clips or the dashboard itself.
Step 4: Remove Car Stereo
In order to add the auxiliary jack you will need to remove the stereo to get at the wires that are located at the rear. Most of the time the stereo is held in place with a few small screws that are easily removed with the Philips screwdriver. Make sure to place the screws in a safe place for reusing when reinstalling the stereo. Slide the stereo out of its position.
Step 5: Disconnect Wires
Most of the time the wires are connected through one simple wiring harness. Disconnect the harness by either pulling it from the plug or prying open the clips that hold it in place.
Step 6: Connect Wiring Adapter
In order to get power to the auxiliary jack you will need to use a wiring harness adapter. Connect the adapter to the wiring harness through the leads.
Step 7: Mount Auxiliary Jack
Drill a small hole in the side of the glove compartment. Thread the wire through the hole and connect it to the auxiliary jack. Mount the jack to the glove compartment with the mounting hardware, or through the compression nut that will hold it to the hole you drilled.
Step 8: Reinstall Stereo
Plug the wires back into the stereo and set it into position. Secure it to the dash with the screws and replace the dashboard panel.
Step 9: Plug in Microphone
Most professional microphones have a three-prong plug in that will need to be reduced to a 3.5 mm jack through the use of an adapter. Make these connections and plug the wire into the jack. Connect the battery terminals so there is power to the stereo and begin testing the car microphone.