I've owned my 2005 Focus 2.0 TDCi Ghia Estate for 4 years now and throughout that time it's had a battery drain. I unhook the negative terminal and the car doesn't get used in the week so have never got round to sorting it out. Fortunately the car doesn't seem to mind, although the bonnet lock does.... I've posted about that elsewhere.
Anyway, a couple of years ago I got as far as buying a multimeter and hooked it up but didn't get much further than comfirming, yes there's a drain.
So, finally spent sometime pulling fuses over the last few weeks and have got to this stage:
(all measured on the 10A scale)
0.54A - Immediately after closing door and locking car
0.38A - After about 5-10 seconds (interior lights go off)
0.23A - After about 10 minutes (dashboard goes off)
So 0.23A (or 230mA) is my background level it seems, a lot more than around 50mA or less as being what would be considered normal and hence why if left connected the battery drops enough to not be able start after perhaps a week or less even.
So on to pulling fuses. First up was the central fuse box in the passenger footwell.
The main one being the F80 fuse (down as battery saver / interior lights), this dropped my drain from 0.23A to 0.13A so a signification part of my drain but not all of it. The F46 fuse (audio) seems to use up 0.01A so not concerned by that.
So next was the auxillary fuse box under the bonnet (will the F80 fuse above removed). All was fine except for the big fuses F3 and F4. If I removed the F3 fuse first I'd drop to 0.06A and then F4 fuse afterwards it would then be down to 0.00A. If I did it the other way, remove F4 first it would drop to 0.11A and then remove F3 to get to 0.00A again.
So overall it is the F80 fuse in the central fuse box and the F3 and F4 fuses in the auxillary box. The F3 and F4 are marked up as 'central fuse box / ignition relays). I think they do override the central fuse box but I already know the issue there. Maybe this suggests it's the ignition that is the problem.
Going to get the car serviced by Ford next week I think (it's long over due) so wondering whether to give them this information and see if they can resolve it. I'd be ok throwing £100-200 at this to be fixed but any more and it's not worth it as can continue on as I am - the cars got 145k on it (previous owner mostly!).
Anyway, would be great if anyone has any suggestions on the F80 central fuse and the F3 / F4 fuses in the auxillary box.