How to Hardwire a Garmin

by David Lipscomb
Digital Vision./Photodisc/Getty Images

Although you can easily tap vehicle power for your Garmin GPS device via a 12-volt outlet or cigarette lighter adapter, there is a cleaner way to install your device. Garmin offers a cable for this task, featuring a mini-USB or proprietary DIN-style connector at one end and four flying-lead conductors at the other. By connecting this cable directly to a 12-volt source such as the vehicle's battery, you will no longer have unsightly wires strung all over your vehicle's dash.

Step 1

Disconnect the positive and negative battery post terminals on your vehicle using a socket wrench with the appropriate insert.

Step 2

Mount the Garmin unit in a location where it does not obstruct your vision, while allowing easy access.

Step 3

Plug the proprietary DIN connector into the matching port on your Garmin device.

Step 4

Route the cable across or under the vehicle's dash toward the driver's side of the vehicle, depending on which offers the cleanest appearance and shortest path to the firewall.

Step 5

Locate an opening in the firewall under the dash and away from pedals. In most vehicles, there is an existing rubber boot with other wires leading into the engine compartment from the cabin.

Step 6

Slide a fiberglass fish rod through the firewall into the engine bay to confirm your selection as a valid access point. Locate the exit point. Fish rods glow, so you should be able to see this easily.

Step 7

Slide the fish rod back out. Tape the flying lead end of the hardwire cable to the end of the rod.

Step 8

Push the rod back through your chosen firewall opening. Unwrap the cable from the rod, and pull the rod back out.

Step 9

Reach in and grab the hardwire cable. Gently pull it up toward you. Crimp a ring terminal connector over the black and red wires. Fold back and tape off the other two, as these are used for connection to a laptop and not applicable to this project.

Step 10

Route the cable to the battery, away from the engine block and other sources of high direct heat. Slide the red wire terminal over the positive battery post. Repeat for the black wire over the negative post.

Step 11

Slide the positive vehicle battery terminal over the post and the Garmin cable wire. Bolt the nut back on. Repeat for the negative terminal.

Step 12

Secure any excess loose cable under the dash with a series of plastic cable ties, preventing the cable from interfering with pedal action.

Remove any batteries from your Garmin unit. Ensure the DIN or USB cable is plugged into the device, then turn the vehicle on. Your Garmin GPS unit should power up with ignition or accessory power, and shut down when the vehicle is off.


  • Never run cabling of any type through a door jamb into the engine bay. Although the method is fast and easy, eventually the door will pinch or cut through the wiring causing a short circuit.


Photo Credits

  • Digital Vision./Photodisc/Getty Images

About the Author

David Lipscomb is a professional writer and public relations practitioner. Lipscomb brings more than a decade of experience in the consumer electronics and advertising industries. Lipscomb holds a degree in public relations from Webster University.

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