Thread: Discovery II battery drain

The normal drain should not exceed 0.05A, for your test to be relevant unplug the bonnet switch, let the bonnet unlocked as to be able to open it without opening a door then make measurements again after more than 1.5 hours as the vehicle to be in the status when all the systems are gone to sleep...report the results and we'll speak then but to check the drop of the drain remove fusible links one by one not fuses at the first stage

Hi Sierrafery,
Thanks for a starting point.
Bonnet switch disabled. Disco sitting overnight. Battery drain = 1.6A
Remove all fusible links one at a time, test. FL8 = 1.0A

Ok, it would be good to cross-check your multimeter though cos even if you found the main path of the drain those figures are looking too high for me, just confirm you didnt open any door before the measurement

but anyway, following that path put back FL8 cos at this point the alternator is the most suspect, unplug the small connector(C0226) from the alternator and undo maxi FL1 one side as to open the circuit and see the drain then.

Have not opened doors or touched anything to bring it out of sleep mode.

Unplugged small lead from alternator and removed FL1. drain = 1.2A

With FL1 and alt lead off and remove FL8 drain = 0.06

Not sure where to go next.
By the way, alternator charges at up to 15 volts with flat battery and drops back as I would expect.

That 0.06 is a good one ... so it seems that the alternator is inducing a 0.4A drain too which is high(provided there was 1.6 before it was disconnected) though the thing becomes strange cos FL8 which cuts dramatically the drain should not affect things with ignition off, next if there is a relay in the bottom slot of the fusebox remove that and see if it make any difference(it might not be one cos it should be only for V8) then unplug C0028 (with FL8 and alternator reconnected).... we are getting close to it don't worry

There is no relay in the bottom slot. Reconnected alt and FL8

Disconnected C0028 and drain = 0.06
Thanks

That's a strange one, i've never seen that before... it seems that there's a leakage through the ignition switch then cos FL8 is linked only to that between the fuseboxes, i cropped and edited the relevant part of the diagram, you can see that from FL8 the path(with red) goes to C0028 -1 and on the bown wire to the switch where it should be isolated from the rest of the circuit with ignition off, is there some auxiliary thing connected to C0028 - 2 which shoiuld be free?

Follow that loom untill the ignition switch to not have some short in it, eventually unplug C0028 and measure resistance against ground on the brown wire, and across brown and the other wires, it should be 0 all the way with ignition off... anyway the drain is there somewhere that's certain now so not SLABS or anything else related, this READ FIRST!! LAND ROVER DISCOVERY 2 99-04 IGNITION SWITCH CABLE WIRE HARNESS is the suspect part but unfortunately ii didnt find it available as new spare