Last Updated on January 20, 2021
The alternator is what your car battery depends on to stay charged. With all the electrical components which exist in vehicles these days, you would never be able to supply energy to all of them with just the battery power alone.
The alternator is what keeps the battery charged so that it can deliver the necessary energy to these components. So, what happens when you have a bad alternator? Can you still jumpstart your vehicle?
When you have a faulty alternator, there is no doubt that you will need to have it replaced as soon as possible. In the meantime, a non-working alternator has probably left you stranded somewhere because your car no longer starts.
However, for some vehicles, it’s possible to jumpstart it with a bad alternator so that you can get it back on the road and drive it to a nearby auto repair shop.
The vehicle only needs enough electricity to power critical components like its onboard computer (engine control unit), fuel pump, and fuel injectors among other things. If you can generate this much electricity, then it will be enough power to drive the vehicle to a mechanic to get the alternator replaced.
How to Successfully Jumpstart a Car With a Faulty Alternator
Below are the five steps for jumpstarting your vehicle if you have a bad alternator. Just remember to be very conservative with your power as you attempt to drive your vehicle to the nearest repair shop.
Without a functioning alternator, your battery will only have a small amount of power before it’s completely drained. Instead of being stuck in a driveway or parking lot, you can instead be stuck on the side of the road.
#1 – Get a Jumpstart from a Good Battery
The first tip should be an obvious one. When you need to get a jumpstart with a bad alternator, you’ll want the other vehicle’s battery to be in good condition and have a full charge.
The reason is that your battery is going to be drawing a lot more energy from this other battery than it normally would as you go to jumpstart your vehicle.
#2 – Connect Jumper Cables
- Attach one red clamp to the positive (+) terminal on the dead battery.
- Attach the other red clamp to the positive (+) terminal on the good battery.
- Attach one black clamp to the negative (-) terminal on the good battery.
- Attach the other black clamp to an unpainted metal part (nut, stud, bolt head, or bracket) in the engine bay of the car with the dead battery. This will provide a proper ground.
#3 – Let the Other Car Run for 4 Minutes
Once the jumper cables are properly connected, have the owner of the donor car (good battery) start their vehicle. The car with the dead battery should be turned off during this time.
After waiting about 3-4 minutes, attempt to start your vehicle which has the dead battery and bad alternator in it. If the car cranks a bit but won’t start, wait another 3 minutes and try again.
#4 – Keep the Accessories Turned Off
Make sure all the car’s electronic accessories are turned off. This means turning off the heating, air conditioning, radio, CD player, GPS, phone charger, or whatever else you normally use in your vehicle to draw power from the battery.
You’ll want to conserve as much battery power as you can so that it can successfully power the necessary components.
It’s worth mentioning that you’ll only want to attempt this during a the daylight when it’s dry out. If you need to use your headlights or windshield wipers, then it will use up too much battery power.
#5 – Drive Straight to the Mechanic
If you were successful at jumpstarting your vehicle from the other car’s good battery, then drive straight to the nearest mechanic. You may have a good 5 minutes or so before the vehicle’s power shuts off again.
Do not go on any major highways or traffic-congested streets. Only drive on the slow-moving streets of your current location.