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There are plenty of reasons to rent a car, from leaving an unreliable car behind on a vacation to getting around a business trip. There is a real hidden danger when renting a car that you may not even realize. And this one action on your part could put you and your family at substantial risk.

Rental companies continually upgrade their fleets with newer-model cars. The latest infotainment systems let you connect — or "pair" — your smartphone via Bluetooth with the car. Once done, you can take calls over the car's audio system, dial from the center console, get directions or stream your music. Others include a USB connection so you can get everything I just mentioned and charge your phone.

When you connect your gadget to a car with Bluetooth, the car stores your phone number in order to make it easier to connect later. It also stores your call logs, which include any contacts you dialed. There’s just one problem: All of that information is saved inside the system and is just sitting around for the next renter to find.

First, we all know that returning a rental car usually happens at the last moment. You’re in a hurry and the flight won’t wait for you. So, give yourself an extra 10 minutes to remove your personal data from the car.

Simply go into the car's settings (it will vary for every car make and model) and loacte your smartphone from the list of previously paired Bluetooth gadgets. There should be an option to delete your phone. That should wipe the call logs and saved contacts. Better yet, look for an option to clear all user data or do a complete factory reset. Talk to the employees at the car rental place if you can't find these options.

If you used the car's navigation system to get around, you have one more step to do. Be sure to enter its settings and clear your location history. You don't want the next person knowing where you've gone, or where you live.

These are also good practices to follow when you sell your own car equipped with this technology. You don't want the next owner to have your private information.

Learn what other technology you should wipe before you sell it, and the steps to removing your information for each one.

Cars can have black boxes. In fact, it's a good bet your current car has one already, and if it doesn't, your next new car certainly will. That's why you should know exactly what that black box is recording, who can get that information and how you can stay in control. Click here to learn more, including how to locate where your car’s black box is located and the data it stores.

We also know that cars can be hacked, as this video shows, and as cars get more advanced, the chance that a car can get infected with a virus increases. If a hacker or previous renter compromised the car’s system, hooking up your phone would give a hacker access to your information.

The obvious solution is to avoid pairing your phone with the rental car's systems. If you want to listen to music, use an auxiliary cable to connect the headphone port on your phone to the audio system directly. For charging, use a cigarette lighter adapter instead of the USB port.

If you want hands-free calling without the risk, you can purchase a third-party Bluetooth audio kit that does the job. It's also a great way to add hands-free calling to an older car.

Hopefully, the privacy concern with car infotainment systems should be going away in the future as Android Auto, Apple CarPlay and similar systems become standard on more cars. These just display the information from your smartphone without storing it. So when you take your smartphone out of the car, none of your personal data stays behind.

On the Kim Komando Show, the nation's largest weekend radio talk show, Kim takes calls and dispenses advice on today's digital lifestyle, from smartphones and tablets to online privacy and data hacks. For her daily tips, free newsletters and more, visit her website at Komando.com. Kim also posts breaking tech news 24/7 at News.Komando.com.