The battery goes dead if left for several days. If the battery is really good it will pass a high rate discharge test and hydrometer test if left for several days it should read 12.6 volts if the battery is good.If the battery would typical go dead if left for a week, leave the battery disconnected for a week and see if it will start when reconnected if so the battery is good. Have they said how much the draw is. About .025 Amps is about right. With an Amp meter connected doors closed, keys out of ignition disconnect the fuses one at a time, disconnect the alternator and fuse links one at a time and see when the "draw" goes away, then with a wiring diagram the components on that circuit are checked to see which circuit or component is draining the battery.
Visitoron Jul 29, 2010
I have a 2005 Jetta TDI with the same issue. (I bought the car used two years ago.) Since I park it in my garage I can keep it charged to keep the car usable while I troubleshoot it - a local electrical shop didn't want my business (what does that tell you) and a local German car specialist shop couldn't duplicate the problem / returned the car unrepaired. So, I purchased a dc ammeter that clamps around wires to measure current flow, since I seem to be on my own. My Jetta was flowing about 0.5 amp with everything off. I disconnected the accessory stereo memory unit in the trunk and it dropped to about 0.15 amp - this helped but did not totally eliminate the problem, which now takes longer to manifest. When the car doesn't start if I open and close the hood it will most often, but not always, then start. Other times if I loosen, wiggle and tighten the (clean) battery terminals the car will then start. One of my sons has a 2002 Golf with a similar issue and a neighbor with a 2000 Jetta has had a similar issue. Earlier today I was reading a Toureg forum thread with a similar issue (see VWvortex.com). So, it seems that several VW models have a similar issue - sounds like an electrical design issue with several models that have similar items drawing too much current with the car off. jclank77@charter.net
Thank you for your reply. I have already done the diagnostic steps you recommended. With a good battery, it will remain charged if I disconnect the battery connection from the negative pole. Regardless of telling what I had done to test the battery, the dealership replaced two batteries over the course of four years, claiming defective batteries was the problem. Recently, I diagnosed there was excess draw on the battery by disconnecting the negative terminal and placing an ohm meter between the negative cable terminal and the positive terminal. My wife also has a TDI Jetta and the difference was about a 1/3 higher. My results were confirmed by the dealership. The problem has been isolating the problem circuit(s). They have isolated all the fuses and all the modules and there is higher than normal resistance on several circuits, but not a root factor explaining why this is happening. So my car remains in the shop. They have engaged VW America's techs to see if they can discern the problem, but so far they haven't figured it out.