[silvershadow]

Yesterday my EOS wouldn't start. I figured perhaps I left the lights on, door hadn't closed all the way, etc. so we jumped the car, it started immediately and I was able to drive to the store and back. When I went out to start it this morning I noticed the car was making a clicking noise before I even got in it. It's just a constant noise that can be heard more from the inside of the car but is also audible standing outside the car. Again the car wouldn't start. We tried jumping it again and it wouldn't turn over at all this time. The clicking noise is still going as well and I can't figure out where it's coming from. Any ideas?

The clicking is most likely coming from a relay that is receiving power from the battery when it should not be doing so while the ignition switch is off. The relay does not need much current to activate and when the load is switched on by the relay, the battery voltage drops, the relay no longer works and clicks off making the noise you hear. As soon as the battery voltage recovers, the cycle starts again and eventually discharges the battery so the car will not start.

If you have some electrical experience, tracing the faulty relay is not difficult and involved removing all the fuses then replacing them one at a time until the clicking starts. Then you need a wiring diagram to identify what relays are on that circuit and the probable cause of voltage being continuously live to the relay. At this point it probably becomes a job for an auto electrician or VW service centre.

Another possibility is a faulty alarm system which is shorting to ground somewhere and the clicking is electronic "noise" coming from the alarm speaker.

 

[silvershadow]

You need a voltage under load test of each battery - a simple voltage test is insufficient as one or more cells maybe incapable of contributing the amperage and voltage necessary for proper functioning of the vehicle electrical system.

A diagnostic test might also help indicate faults that are associated with your problem - unless you have the experience and knowledge to do so, you need help from a VW specialist.