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Q: Pulsating Lights

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I have a 2003 Jetta Station Wagon with a 1.8T 5spd. When the car is idling and while I'm driving the dashlights and headlights pulsate. The car also idles up and down a bit and the fuel pump makes a whirring noise. I've replaced the fuel filter, spark plugs, and the alternator. Any help is greatly appreciated.

My car has 224000 miles.
My car has a manual transmission.

A: The battery and charging system is most lik...

The battery and charging system is most likely the malfunction. If the battery is shorting out internally it would cause the alternator to not charge. There is a technical bulletin about not using re-manufactured alternators on these cars since they had problems of not charging properly. You should have your vehicle system checked by a mechanic like one from YourMechanic to see if the battery and cables are good and if the alternator is charging properly.

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A: I have seen this quite a few times on this ...

I have seen this quite a few times on this vehicle. It is almost always caused by loose or dirty ground connections. I typically remove the ground connections on the negative cable first and clean them and make sure they are tight. If those are fine I then check the grounds connected to the engine. Some of the time it can be a bad connection at the module, but most of the time it is the grounds. If you are going to have this repaired, consider YourMechanic, to have a certified mechanic come to your home or office to https://www.yourmechanic.com/services/service-battery-cables.

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