2002 TDI Electrically Dead

[rgb123]

Hi All,

I stupidly left the lights on my Landy on last week and returned to find a dead battery. It died at work, so I needed to remove the battery to charge it. Having charged the battery, and verified it is charged with a multimeter, the Landy is now totally dead electrically.

I can see 12 voltage across the battery but nowhere else.

I've probed all fuses, including those under the drivers seat and none have any volts. I thought "immobiliser" but there is no red light on the dash, and looking at the circuit diagram there is nothing between the battery and fuse 7 which goes into the ECU. Fuse 7, as the with the others, has no volts on either side.

Either I am missing something or gremlins have chewed through a wire at exactly the same time as the battery went flat. I know which one I suspect.

Any suggestions gratefully received.

[Snagger]

Are the battery leads clean? Do you have an isolator anywhere? You might have a wrecked battery that is getting only a surface charge but is not deep charging - running a battery completely flat can do that.

[Mo Murphy]

I'm sure i already replied to this !

check that the power supply to the under seat fuse box from the positive terminal is connected.

Mo

[Tanuki]

Is the battery actually OK? Modern batteries really hate 'deep discharge' and often cannot be successfully recharged after such treatment.

Though your multimeter may show +12V at the terminals when the battery has no load on it, what really matters is whether the battery can still manage +12V when you're pulling a good few tens of amps from it. An even totally knackered battery can show +14V at the terminals under no-load condition but the volts drop off when you try to draw any power.

I'd suggest you try a jump-start: if that works then look at a new battery.