Garmin Dash Cam 35 Does Not Detect SD Card

Even though it may look fully inserted, it may not be. Check to make sure it is pushed in all the way, until it clicks. This is a sure sign it is fully in the card slot.

Try formatting the card directly in the Garmin Dash Cam 35 menu screen. To do this, ensure the camera is powered on, then navigate to the format option through the Settings > Camera menu. If this does not work, try formatting it separately on a computer.

The pins/connectors/contacts where the SD card is read by the slot may be dirty or worn. Check the card, wiping the terminals on the SD card with a lint-free cloth/microfiber towel, or even isopropyl alcohol.

Ensure the dash cam has the most updated software by updating it through the Garmin Express application on your personal computer.

Test the card in another device to see if the dash cam is the problem, or the card is simply faulty and needs to be replaced.