Won't start - 2nd time this week
 

Monday morning my 2002 S8 was flat as a pancake and had to be jump started off my wife's mini (oh, the shame!:o). I assumed that, as I'd cleaned it inside and out on the Sunday, that I'd switched something on accidentally and the battery had drained whilst it was left standing on the drive.

It was fine all week. Five 35 mile each way commutes in the dark and the odd trip to the shop at lunchtime.

But tonight, came home, went out an hour later to pick up my daughter, waited outside her place of work for 10 minutes with side lights and the TV on and....flat as a pancake again.

Doesn't really sound like a battery or alternator fault - but I might be wrong...

...any ideas on where to start guys?

Volt meter across the battery terminals when the car is running should give about 14V. If it doesn't then Alternator problems???? or bad earth . My thread here may help.

As Mike says above..

But given the age of the car, it could just be that the battery is going and with the extra load on the dark mornings/nights it's just not getting itself sorted anymore.

Well I only drove about half a mile after the jump start last night, left the car outside overnight and it started this morning! A bit sluggish, but there you go.

The voltmeter shows 13.8 volts across the battery with the engine running...so where are these pesky earths?

Drivers side wheel arch, on the chassis rail you will see a wee black box that has the cable from the battery going in and the lead to the starter motor and alternator going out. Next to it is the earth lead from the engine to the chassis.

Front or back? I've got the front driver's side wheel off and can't see a black box....

It must be hard to find as - following earlier thread - I asked my garage to check it before last winter. They couldn't find it and so didn't do it, but did clear scuttle drains etc.

Found a black box above the battery in the boot, but everything is like new in there.. Put a 10mm socket on and tightened each connection up - but I suspect that's not what I'm looking for is it?

BTW - the battery has 12.25 volts across it - is that OK?

Still, off-side front wheel is now very clean!

http://i25.photobucket.com/albums/c7...37-resized.jpg

This photo shows the brown earth wire left of the socket ratchet. The purple connector is next to the battery connection box.

The schematic

http://forum.a8parts.co.uk/attachmen...1&d=1288441791

Silly Q... But was this maybe moved on the FL model?