# To what extent can alternator troubles manifest?

**URL:** <https://community.cartalk.com/t/to-what-extent-can-alternator-troubles-manifest/36081>\
**Category:** Maintenance/Repairs\
**Tags:** sensors, colt, dodge, alternators\
**Created:** [September 3, 2009, 8:30pm UTC](https://community.cartalk.com/t/to-what-extent-can-alternator-troubles-manifest/36081 "2009-09-03T20:30:20Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![dynosour](https://avatars.discourse-cdn.com/v4/letter/d/8e8cbc/32.png) [@dynosour](https://community.cartalk.com/u/dynosour)\
**Post date:** [September 3, 2009, 8:30pm UTC](https://community.cartalk.com/t/to-what-extent-can-alternator-troubles-manifest/36081/1 "2009-09-03T20:30:20Z")

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could a poorly performing alternator be responsible for tripping several diagnostic trouble codes about bad sensors? and could the same account for intermittent opening of a master relay switch while driving? (if so, my multitude of problems could have one, fixable solution) I do have a multi-tester, so any advise on testing alternator output woould be appreciated too. thanks.

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**Author:** ![bennyandthejets](https://avatars.discourse-cdn.com/v4/letter/b/b487fb/32.png) [@bennyandthejets](https://community.cartalk.com/u/bennyandthejets)\
**Post date:** [September 3, 2009, 9:12pm UTC](https://community.cartalk.com/t/to-what-extent-can-alternator-troubles-manifest/36081/2 "2009-09-03T21:12:11Z")

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I would think not, unless it was very poorly performing. If the voltage was fluctuating from the alternator low and high, then maybe, but usually it either works or it doesn’t. At least any test you can do will show that. Take you multimeter and stick it on your battery terminals. Read the voltage. Should be about 12.5 volts DC or so. Now, leaving it there, start your car, the voltage should jump up to around 13.5-14.5 volt, DC. If all that checks out and it is holding steady at 13.5-14-5 (roughly)now with your car still runing, turn on you high beams, heater fan on high, your rear window defrost, anything else you can to put a load on the alternator. If with all your stuff turned on, you alterater is still producing the same voltage (roughly), and holding steady, your alternator is working fine. Don’t leave your rear window defrost on too long in this weather or it might burn something up.

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**Author:** ![willey](https://avatars.discourse-cdn.com/v4/letter/w/a9adbd/32.png) [@willey](https://community.cartalk.com/u/willey)\
**Post date:** [September 3, 2009, 9:51pm UTC](https://community.cartalk.com/t/to-what-extent-can-alternator-troubles-manifest/36081/3 "2009-09-03T21:51:48Z")

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Yes. Low system voltage can cause weird things to happen. Have the charging system checked.

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**Author:** ![dynosour](https://avatars.discourse-cdn.com/v4/letter/d/8e8cbc/32.png) [@dynosour](https://community.cartalk.com/u/dynosour)\
**Post date:** [September 4, 2009, 12:24am UTC](https://community.cartalk.com/t/to-what-extent-can-alternator-troubles-manifest/36081/4 "2009-09-04T00:24:13Z")

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the alternator (atleast on a bench test) checked out ok… rats!