A car that will not start can interrupt a workday quickly. Reaching for jumper cables may feel like the obvious next move, but first check whether the procedure is appropriate for your vehicle and your surroundings. A little preparation is more useful than trying to remember a cable sequence from a different car.
Find the instructions for the actual vehicle
Open the jump-starting or roadside-emergencies section of your owner's manual. Confirm the model year and powertrain, then identify the approved connection points before bringing any clamps near them. Some vehicles use designated posts away from the battery. Ford's illustrated instructions for one hybrid application, for example, describe under-hood jump points even though its battery is in the trunk.
That example is a reason to consult your own manual, not a diagram to copy onto another model. Read the complete sequence, including disconnection and any operating instructions afterward. If a label, connection point or instruction is unclear, stop and ask a qualified service provider to handle the job.
Check the situation before opening the hood
If reaching the engine compartment would place you beside moving traffic, do not attempt a jump there. Arrange roadside assistance from a safe location. At home or work, consider whether there is adequate space and visibility to follow the instructions without rushing or reaching across obstacles.
With the vehicle secured as its manual directs, look for obvious battery damage without touching residue or opening the case. Interstate Batteries' safety guidance calls attention to bulging, cracks, heat damage and unusual sulfur-like odors. If the battery is damaged, leaking or unusually hot, leave it alone and get professional assistance rather than attempting to boost it.
Do not assume every vehicle can help another
Check the assisting vehicle's instructions as well as the disabled vehicle's. A hybrid or electric vehicle is not automatically an appropriate donor. Tesla's Model 3 instructions explicitly say not to use that vehicle to jump-start another vehicle, and distinguish procedures for different low-voltage battery types.
A portable pack also needs to match the application. Read its voltage, compatibility and operating instructions before use; do not rely only on a large number printed on the box. Interstate's portable jump-starter guide starts with reading the equipment manufacturer's directions and understanding its indicators. An unfamiliar warning light is a reason to consult those instructions, not override a protection feature.
Keep the important precautions in view
Battery gases can ignite, so keep flames, smoking and sparks away. Ford warns against selecting an arbitrary grounding point such as a fuel line or an electrical component, and says to keep cables clear of belts and fans. Use only the connection locations and sequence specified for your vehicle and equipment.
Interstate also recommends eye and hand protection, removing jewelry, and preventing clamps from touching each other. If you cannot position the cables securely or identify the terminals confidently, there is no benefit in guessing. Keep others clear of the work area and ask for help.
Make a plan after the car starts
A successful start does not establish why the vehicle failed to start or prove that its battery is healthy. Interstate describes jumping as temporary assistance and recommends follow-up testing. Record what happened, whether the vehicle had been parked for a while, and whether it has happened before. Share observations without deciding which component must be replaced.
For replacement-service information, see our battery service page or call 480-818-6699. We'll contact you to confirm your visit.
