X308 4.0L 1991 Battery Drain Problem

Hello Folks,
I have a persistent battery drain problem on my 2001 X308 4.0L. I have checked everything off of course and the usual simple things but the batt still runs down. Wondered if anyone had encountered this and can proffer advice. Thanx in anticipation. Rgds. Charlie.

Have you done a parasitic draw test?

Is your sounder audible when you arm and disarm the alarm? Does the heater work? Fog lamps? I’m willing to bet you’ve got a shorted sounder.

If that’s all good then put a multimeter set to measure amps across the battery terminals and, with everything off, pull each fuse and check whch one causes the current to drop. It is a monumentally time-consuming job but, in reality, the only real way to determine the culprit. My money’s still on the sounder! :slight_smile:

Just about to get on with it. Tks.

The heater, fog lamps and everything else seems to work and the Sounder sounded like good advice so sounded it out and the sounder does’nt work so sounds as tho it may be a sound bet as you suggest. Is it possible to isolate the sounder?? Thanx and Rgds.

From memory, you access it via the (UK) passenger side wheel-arch and simply unplug it. Happy to be corrected on both counts.

Checking it out i found a 0.45 amp drain with everything off inc the boot lights and a resistance check on the +ve lead gives approx 950ohm. So clearly there’s a problem which i will just have to progressively check out… Thanx for your prognostication on where the sounder is located; you can search for hours trying to find these items and its the sort of thing that’s perhaps not in the manual; will advise if i find it. Would appreciate it if anyone can confirm its location. Rgds.

One other thought, my ‘99 XJR had a dodgy earth lead that was causing me trouble, might pay to check if that gets hot when you use the car.

Remove fuse 3 and see if draw drops

Do it before winter

Ok will check that. Thanx. Regards.

Ok have done that so will see what happens. Rgds.

Just to save you a bit of typing your are perfectly OK to reply to more than one poster in the same post.

Fuse 3 is in the fusebox under the bonnet. The large one
Front fogs should stop working if you get the correct fuse.

It gets cold inside with this fuse removed too.

On my car this is the 30A fuse?

ee foto attached. Reason for the foto is that the fuse layout seems to vary between model years.Thanx Rgds.

Isn’t it top right ? Red fuse ?

I think I can see a 3 in black plastic

Just had a look with a mag and #3 in my fuse box is the 3rd one down on the RH column the 10A. The numbering starts at the top of the RH column #1 and progresses round to the LH column. Rgds.

Yes, I thought that was the case

The X308 does NOT ‘shut-down’ the electrical systems all at once.
The systems ‘power-down’ in stages and it take about 20 minutes to fully ‘go-to-sleep’ after the car is closed and left alone.

The quiescent draw should be about 30ma when the car is fully powered down.

The initial drop is over an amp and then 800ma, then 300ma and so on…till it gets to about 30ma.

The Body Processor is always waiting for the door to open, or the alarm triggered, or a keyfob transmitter, or?

Once a door is opened or the ignition switch is activated, the entire sequence needs to be repeated and WAIT. (again)