Jump Starting a Car

Practical advice to get you back on the road

You bought the emergency car kit. You have the appropriate sized jumper cables for your vehicle (Jumper cables can come in various thicknesses or gauges; smaller four cylinder vehicles require smaller cables than big diesel pick-ups, as an example. The thicker the cable, the more electrical current they will flow. Fatter cables will do a better job in the cold. Generally you get what you pay for). What to do next?

How to Safely Jump-Start Your Car

Jump-starting a car with a weak battery can be dangerous if proper procedures are not followed. ALWAYS CONSULT YOUR OWNERS MANUAL FOR VEHICLE SPECIFIC INSTRUCTIONS. Be sure to wear eye protection and long-sleeved shirts as batteries do contain acid. Remove any jewelry or rings which might become a ‘ground’ path during the process of jump-starting your vehicle, causing bodily injury. Batteries emit an explosive gas that can ignite if jumper cables are not connected properly!

Step 1 – Position the cars close enough for jumper cables to be connected, but do not allow cars to touch.

Step 2 – The transmission on both vehicles should be in park, or in neutral with a manual transmission. The parking brake should be on and the IGNITION in the ‘off’ position. Be sure all accessories such as headlights, dome lights, and radios are OFF. Unplug any cigarette-lighter accessories such as cell phones, radar detectors, etc. Jump starting can send a voltage spike through the electrical system that can damage these gadgets.

Step 3 – Identify the battery post’s as either POSITIVE (+) or NEGATIVE (-). Positive posts or terminals are typically bigger than negative posts or terminals. Some cars have a positive terminal to hook the cable to that is not actually on the battery itself. Connect one end of the positive cable to the positive terminal of the good battery. Remember that the ‘red’ or ‘orange’ cable is ‘positive’ and ‘black’ is negative.

Step 4 – Attach the other end of the positive (red/orange) cable to the positive terminal of the disabled battery.

Step 5 – Connect one end of the (black) negative cable to the negative terminal of the good battery. A quick wya to remember this procedures is: positive – to positive; negative -to-negative.

Step 6 – Attach the other end of the negative cable to the engine block or alternator mounting-bracket of the disabled car, as far from the battery as possible. Do not connect the negative cable to the negative terminal of the discharged battery, as this can generate a spark, which could cause the discharged battery to explode.

Step 7 – Start the engine on the car providing the jump. Let the bad battery charge for at least a minute before attempting to start. When attempting to start the disabled vehicle, don’t crank the starter for more than 20 seconds. If it doesn’t start in 20 seconds, wait two minutes before trying again. If it cranks but won’t start it may require more charging time before another attempt.

Step 8 – When the disabled car is running, disconnect the jumper cables in the reverse order from which they were connected. Take care to avoid moving parts such as fan blades. Also make sure the cable’s clamps do not touch until all four clamps are disconnected from the two vehicles.

After the vehicle with the discharged battery has been started, take the vehicle to a reliable repair facility, such as a AAA-approved Auto Repair facility, to have the electrical system checked and the cause of the discharged battery diagnosed and then repaired.

Can’t Get a Charge, or Want Some Help?

AAA can come jump start your car for you if you don’t have access to jumper cables and another vehicle, are not getting a charge, or don’t want to try to jump start the car yourself. If you let us know you have a battery problem in the Denver metro, Colorado Springs, or Boulder areas, we can even dispatch a special battery service vehicle to you. The technician can test the charging system to tell you what is happening, show you the results, and if you desire, can sell and install a new battery on the spot. You can even make an appointment for battery services in these areas! Learn More.