What You’ll Need:
An auxiliary jack is a device that uses cables to connect an MP3 player to a car audio system via the headphone connection. These are becoming increasingly common in newer vehicles, and generally most will be compatible with any and all phones and MP3 players. However, in some cases, the female port (the port in the car itself) may be sized incorrectly it or it may be damaged. Following the guidelines below will enable you to switch out your jack for a proper functioning alternative.
Step 1 – Check Your Car Stereo Female Aux Input
The first thing that you must ensure is whether the female input of your car stereo fits the aux jack of your sound accessories. If it does not, you may need to identify the size of the aux jack that will fit to that of your car stereo.
Step 2 – Determine the Size of Jack You Need
If you have identified the size of the male aux jack that will fit onto your car stereo’s female aux input, shop for the replacement at the nearest electronic store. It will be helpful if you dismount your car stereo from your car, and bring it along with you to precisely determine the size of the jack that you are looking for.
Step 3 – Prepare to Replace the Old Aux Jack
Now that you have the exact size you need to fit in to your car stereo, cut the incompatible aux jack from connection using wire cutters. Then, remove a small part of the rubber casing as well, approximately 1/4 inch to expose the inner wires. Trim the rubber on the connectors of the male aux jack as well.
Step 4 – Join the Cable and Aux Jack
Before joining the exposed wire of the cable onto the connector of the aux jack, make sure that you have inserted the cable into a shrinkable wire. The length should be enough to cover the joint between the connector of the aux jack and the exposed wire on the cable.
Step 5 – Securing the Joint
Using a soldering iron and copper wire, solder the joint between the wire and aux jack connector. Then, mix a small amount of epoxy putty to cover and seal the joint. Allow it to dry for the time recommended on the packaging.
Now that the connection between the aux jack and the cable is secure, slide the shrinkable wire where the cable was earlier inserted to the spot where the joint is situated. Heat the shrinkable wire above a candle/lighter flame for about ten seconds. This will tighten it to leave a neat and good fit on the joint. With that complete, you should be finished and able to use your auxiliary port once more.
source- http://www.doityourself.com/stry/how-to-replace-an-aux-jack