# testing alternator while in car

**URL:** <https://forums.speedlife.net/t/testing-alternator-while-in-car/248617>\
**Category:** Shift518 Automotive\
**Created:** [November 25, 2009, 7:48am UTC](https://forums.speedlife.net/t/testing-alternator-while-in-car/248617 "2009-11-25T07:48:21Z")\
**Posts on this page:** 1\
**Showing post:** 27

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**Author:** ![88slowmarro](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/88slowmarro/32/6339_2.png) [@88slowmarro](https://forums.speedlife.net/u/88slowmarro)\
**Post date:** [November 26, 2009, 9:33am UTC](https://forums.speedlife.net/t/testing-alternator-while-in-car/248617/27 "2009-11-26T09:33:01Z")

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> [@Where did my voicemail go (VZW)?](https://forums.speedlife.net/t/where-did-my-voicemail-go-vzw/26343/12):
>
> Yes the disconnecting the battery trick does work (possibly not on all cars). I have done it on my jeep and my dodge to check it. ONly disconnect the positive, not the ground from the battery and keep the alt. positive connected to the car. If it continues to run your alt is good. If it dies however, it does not necessarily mean the alt is bad as it could still be a bad ground/connection, etc.

great way to blow out b.c.m,s and other modules by disconecting the battery while running like i said before your testing with a dmm and gettin 14 and change you should be fine next though run all your acces while doin it so its under load

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