# Bad Alternator..? .. engine dies when lights turned on

**URL:** <https://community.cartalk.com/t/bad-alternator-engine-dies-when-lights-turned-on/166308>\
**Category:** Maintenance/Repairs\
**Tags:** plymouth, laser\
**Created:** [June 25, 2020, 1:45am UTC](https://community.cartalk.com/t/bad-alternator-engine-dies-when-lights-turned-on/166308 "2020-06-25T01:45:16Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Tom777](https://avatars.discourse-cdn.com/v4/letter/t/e79b87/32.png) [@Tom777](https://community.cartalk.com/u/Tom777)\
**Post date:** [June 25, 2020, 1:45am UTC](https://community.cartalk.com/t/bad-alternator-engine-dies-when-lights-turned-on/166308/1 "2020-06-25T01:45:16Z")

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1. 

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My car would not start...no battery power at all . My neighbor jumped me...after running a few minutes , he told me to turn on the lights, I did and the car engine immediately died.....and had to be jumped started again.....he says I need a new alternator. Is he right? Is the alternator test Auto Zone does reliable?
```

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**Author:** ![davepsinbox\_157004](https://avatars.discourse-cdn.com/v4/letter/d/73ab20/32.png) [@davepsinbox\_157004](https://community.cartalk.com/u/davepsinbox_157004)\
**Post date:** [June 25, 2020, 1:47am UTC](https://community.cartalk.com/t/bad-alternator-engine-dies-when-lights-turned-on/166308/2 "2020-06-25T01:47:16Z")

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I’d certainly start by having both the alternator and battery tested.

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**Author:** ![Nevada\_545](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nevada_545/32/41232_2.png) [@Nevada\_545](https://community.cartalk.com/u/Nevada_545)\
**Post date:** [June 25, 2020, 2:12am UTC](https://community.cartalk.com/t/bad-alternator-engine-dies-when-lights-turned-on/166308/3 "2020-06-25T02:12:17Z")

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When operating with a dead battery the system voltage will be unstable, switching on lights can bring the system voltage below operating level before the alternator can react. I have had engines stall while pulling into the shop by just stepping on the brake pedal (brake lights on).

I suspect your car has been sitting unused for a period of time, recharge the battery with a battery charger.