# 2003 VW Jetta 2.0 Battery Drain problem



## ssgfrazier (May 14, 2016)

I have been working on a 2003 VW Jetta for the past 6 months attempting to get it to the no worries drivable state. My battery keeps draining. Initially it was draining while sitting, changing the drivers side window/lock controls seemed to fix that problem. Then the car would not start, I replaced the |high voltage fuse box" on top of the battery, which initially started to charge the battery. This week the car died while driving, the first symptoms were rough idling and slowed acceleration. I took the alternator and battery in for testing. The alternator tested good, and the battery tested bad. The battery was 6 months old. I replaced the battery, and spark plugs. 2 days later the car again died while running, which tells me that 1} the battery is not charging, and 2} the alternator's charging capabilities is not reaching the battery. My question is, would the wireing harness that connects the alternator to the high voltage fuse box show any outward signs of being faulty? Looking at it, the cable does not seem frayed, or damaged in any way, and the connections seem good. Would this wire be the next plausable part to replace in the charging system or is there something I am missing?

To reiterate, battery is 2 days old, alternator tested good, high voltage fuse box 3 weeks old. Battery not charging and alternator is not supporting car when running.


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## Ed52 (May 21, 2001)

Look for the Mk4 forum further down the page and ask for help.
I would check the body grounding points. There is one under the battery tray - might be a good place to start.

Do you have a volt/ohm meter? It's an essential tool to diagnose electrical issues. Do a search on how to use for automotive troubleshooting (or pay big$ to have a mechanic do that.)

There is a single wire connector at the alternator(perhaps blue, small diameter) that 'turns on' the alternator to charge battery.


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