Having a GPS device can be a major convenience if you are lost and need to find your way or if you want to keep track of someone you love. However, it can be an inconvenience if you don't want somebody to know your own whereabouts. If you suspect that your vehicle has a GPS tracker on it, the units are easy to find and disarm, provided that you have the right tools.
Do a visual and tactile search first. Begin by looking at the interior of your car and checking under the seats and in the glove box. Also check underneath the car, inside the bumpers, inside the boot and under the hood. You are looking for a black box about the size of a deck of cards.
Buy a GPS bug detection device. You can purchase these online at any spy and gadget store (see Resources) or on eBay. As of 2010, these cost about £48-$400, depending on what your needs are.
Turn on the detection device and begin sweeping the vehicle by moving the device alongside it. It works by picking up any transmissions that the GPS device is emitting. If the detection device finds one, it will begin beeping rapidly and a light will blink.
Scan your vehicle several times at different intervals, because there are some semi-passive GPS systems that only emit signals intermittently.