# Headlamps, fiber optics brighten and dim alternately

**URL:** <https://community.cartalk.com/t/headlamps-fiber-optics-brighten-and-dim-alternately/16735>\
**Category:** Maintenance/Repairs\
**Tags:** headlights\
**Created:** [July 15, 2008, 3:48am UTC](https://community.cartalk.com/t/headlamps-fiber-optics-brighten-and-dim-alternately/16735 "2008-07-15T03:48:18Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![p47koji](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/p47koji/32/885_2.png) [@p47koji](https://community.cartalk.com/u/p47koji)\
**Post date:** [July 15, 2008, 3:48am UTC](https://community.cartalk.com/t/headlamps-fiber-optics-brighten-and-dim-alternately/16735/1 "2008-07-15T03:48:18Z")

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My wife’s '05 Magnum SXT headlamps and toys lit up w/fiber optics alternately go bright then go dim but not at idle. I replaced headlight switch for heck of it and just made a deposit at Bank of Chrysler. Sounds like a ground? How best to find it - duh!

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**Author:** ![Joseph\_E\_Meehan](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/joseph_e_meehan/32/21_2.png) [@Joseph\_E\_Meehan](https://community.cartalk.com/u/Joseph_E_Meehan)\
**Post date:** [July 15, 2008, 10:41am UTC](https://community.cartalk.com/t/headlamps-fiber-optics-brighten-and-dim-alternately/16735/2 "2008-07-15T10:41:27Z")

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I would have the charging system checked. Many auto part stores will do this for free.

Checking grounds is also a very good idea, as well as both ends of all battery cables, but this are not free unless you are doing them yourself.

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**Author:** ![p47koji](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/p47koji/32/885_2.png) [@p47koji](https://community.cartalk.com/u/p47koji)\
**Post date:** [July 15, 2008, 4:31pm UTC](https://community.cartalk.com/t/headlamps-fiber-optics-brighten-and-dim-alternately/16735/3 "2008-07-15T16:31:07Z")

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Thanks for the advice, Joseph. Will give it a shot. You wouldn’t have any suggestions on how to cure my wife’s “original curb impact designs” on the chromed American Racing TorqThrusts I put on her Magnum?? (Just kidding on seeking the advice - not kidding about the curb impacts - plural.)

Thanks again.

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**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\
**Post date:** [July 15, 2008, 7:20pm UTC](https://community.cartalk.com/t/headlamps-fiber-optics-brighten-and-dim-alternately/16735/4 "2008-07-15T19:20:34Z")

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I agree with Joseph. This sounds like an alternator or regulator problem.

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**Author:** ![p47koji](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/p47koji/32/885_2.png) [@p47koji](https://community.cartalk.com/u/p47koji)\
**Post date:** [July 17, 2008, 3:36am UTC](https://community.cartalk.com/t/headlamps-fiber-optics-brighten-and-dim-alternately/16735/5 "2008-07-17T03:36:50Z")

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And thank you, too, the same mountainbike… For what it’s worth, this car’s cool-looking but the German influence in the electrics suck. Look at the speed control setup… The electrics have been nothing but trouble. The horn ring went out, the dash cluster had to be replaced, and now this…