How to Jump Start a Ford Flex

1. Connect the positive (+) jumper cable to the positive (+) terminal of the discharged battery.
2. Connect the other end of the positive (+) cable to the positive (+) terminal of the booster vehicle battery.
3. Connect the negative (-) cable to the negative (-) terminal of the booster vehicle battery.
4. Make the last negative (-) connection to an exposed metal part of the stalled engine, away from the battery and fuel injection system, or to a ground point if available.
5. Start the booster vehicle and keep engine speed between 2000 and 3000 RPM, then start the disabled vehicle.
6. Run both engines for three more minutes, then remove the cables in the reverse order of connection.

• Do not attach the positive cable to the studs or L-shaped eyelet above the positive (+) terminal; high current may damage the fuses.
• Do not connect the second cable to the negative (-) terminal of the battery being jumped; a spark may cause an explosion.
• After removing the cables, let the engine idle for at least one minute.

Source: 2019 Ford Flex owner's manual, PDF pages 225, 226. Steps are summarized in our own words (AI-assisted, checked against the cited pages 2026-10-18). Other model years can differ; your manual has the final word.