Power Drain Logging

Reading this thread I have had similar with my Defender TD5, though not the D2 V8. Will be fine for ages and then just suddenly not start. Have done all similar and cannot trace the problem.

True. Even 5A drain is only 60W. I would rather fix the problem than apply a bandaid though.

Right, made some progress tonight. The alarm went off at 930pm and the lad gave me the puppy dog eyes and asked me to help. It would not lock/unlock with the remote so he used teh key. The superlock on the others doors would not come off. It started fine.

The amazing thing is that the lad might have found the cause all by himself!!!! He could hear a slight buzzing sound under the dash. I got my decrepid ears under the steering wheel and traced it to the fuse box. It is annoying that during my previous attempts to find the issue I had partially removed this fuse box but could see (nor hear) anything wrong. Removing the battery lead made the sound go so we were onto something!

I removed the whole fusebox, opened it up and found the bottom part of the circuit board covered in black sludge.

I have previously thought that there is a mysterious current drain. I now think that is caused by the fuse box shorting itself.

Thinking back, the issues do seem to have been worse during rain. I had found a leak in the top driver's side of the windscreen before and told the lad to seal it up. Turns out he didn't do a very good job. If you want something done yada yada yada....

Ordering a new fuse box. Will seal the window and hopefully all will be well and I can get back to fixing my own cars!!!!!!!

Is by any chance your vehicle converted from air suspension to coils but not set to that and the "hardware" left in place? cos then it might be a logical explanation

No spension mods.

Brit Parts have just informed me that teh fuse box is discontinued. YQE000251G. Anybody know of elsewhere that might stock one? I don't really want to go 2nd hand as you just never know if it has the same issue.

I have cleaned the original one but am hesitating to re-install it. The PCB tracks look fine so maybe it might be worth a go?

Just wrote a long and iteresting (well I thought so) post but the stoopid system said it was too busy to post it and it disappeared. grrrr This is the cut down version...

Attached is a picture of the PCB inside the passenger fuse box. I have cleaned off the sludge with contact cleaner and examined the tracks. Although the paint has peeled off the tracks appear to be intact and there are no short circuits. I believe the sludge was allowing some amount of short circuiting.

Electronics experts - does it look like it can be reused?

I thought I would investigate whether my hypothesis that this sludge was causing the random parasitic draw. There are 4 tracks that were in the sludge (as can be seen by the flaking paint). Using a multimeter to work out were these tracks lead to I determined that they go to;

Relay 6 - unknown circuit
Fuse 12 & 13 - 'Relay-Window' 'Lift-Rear' 'Ecu Sunroof'
Battery - via inertia switch and engine compartment fuse box
Fuse 32 - accessories circuit
Front LH Headlamp

Basically one track is permanently 12v.....BINGO.

The only thing connected to the accessories circuit is a Navman which I doubt draws much current. However, with multiple circuits involved, the electrons could be leaking into several places.

I could be full of merde but I think I have nutted out his intermittent and wierd issues...........

I would give it another go. The worst that can happen is it fails again.

Found a dirt cheap new genuine item earlier this evening so grabbed it.

A late follow up to this thread.

Although we bought a brand new fuse box we did not use it . I reinstalled the old cleaned up box and the car was faultless. Definitely a short circuit caused by the rain penetrating the front windscreen seals and leaking into the fuse box. Win.

After all that hard work, he sold the car grrrrrrr