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Q: I was driving down the road just fine all of a sudden my battery light came on for a second then all of my lights came on and then

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was driving down the road just fine all of a a sudden the battery light came on for a brief second and then all the lights came on... then also there was a message that said it was using reserve battery or something and to get everything serviced like I said ATS was off and things and it said service battery stuff like that. It took about a mile to find a place to pull over just as I was pulling into the parking lot the engine powered down so I can only go about 5 miles an hour I got into a parking space and shut the engine off. When I turn on my headlights I have strong headlights my windows power up and down but when I turn my key it only cranks about twice and it will not start. I have a hundred and sixty seven thousand miles on this vehicle, and 3 days ago I had to replace the air condition compressor and all the other parts that go with that. I looked down in and underneath and pulled on the belt and it seems tight.

My car has 172000 miles.
My car has an automatic transmission.

A: Hello. Obviously, there’s an electrical iss...

Hello. Obviously, there’s an electrical issue. To rule out the simple and obvious possibilities have the battery load tested at a major, reputable battery store (this is a common test; they have the tester) to be sure the battery doesn’t have a faulty cell and/or is simply too weak. If the battery happens to pass the load test, but only marginally, replace it outright anyway especially if it’s already 4 years old. Batteries don’t last forever and they are important.

The second obvious and related issue is the condition of the charging system. Regardless of the status of the battery, you should check the output of the alternator. If you by chance are able to get the car running (because you bought a new battery and that "worked"), when the car is running, you should see something like 13.9 to 14.7 volts at the battery terminals (there are specifications for your year, make and model). If you need help with these initial diagnostics, by all means a certified technician from YourMechanic can be dispatched to your home or office to assist with this. If both these checks do not reveal the issue, it would have to be diagnosed in person. Best wishes with this.

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