Cigarette lighter sockets are quite different than the power sockets you find on many newer vehicles. They have special high-current contacts that, due to how they are designed, can be accidentally shorted out by the mismatched contacts on accessory plugs, including those for cell phones. It can depend on the orientation of the plug when it is inserted. These sockets also have a thermal cutout right under where the wire plugs into it. That is a safety switch in case the lighter does not pop out and turn off. That thermal cutout can go the entire life of the vehicle without ever tripping, but if it does, it will reset automatically after it cools down. The problem is those contacts can become arced or pitted.
To identify where to look for the cause of this problem, use a test light and test on the contact right in the center of the socket. You can use a voltmeter for this, but it can easily give misleading results that we need to do some follow-up checks for.
If you do not find twelve volts on that contact, you'll need to gain access to the back of the socket. Pull the wire off, then check for twelve volts on it. If it is missing there, you're back to the fuses. If you do have twelve volts, the socket will need to be replaced.
May 14, 2017 at 5:39 PM
