Hi Folks, tis a 1990 200Tdi Disco, had a new batt 2 weeks ago, everything was fine whilst I was using it regularily, no red lights etc, however its been of road for a week, MOT stuff, and is now flat as the proverbial, I have a radio with memory, no alarm system(well its switched off) central locking does not function, any ideas what is draining the batt.
With everything switched off and the keys out, put a multimeter (set to mA) from battery + to earth. This should read zero, although alarms and memory radios will take a few mA. Anything more than a few mA and you have a current drain that will flatten the battery over a period of a couple of weeks.
Make a note of the radio code, just in case. Position the multimeter so that you can see it while working on the main fusebox. Pull out one fuse at a time until you get a sudden drop to zero on the meter. You have just disabled the circuit that is causing the drain. Troubleshoot from there. On mine, it turned out to be the bonnet switch for the perimeter alarm which was draining about 30 mA, even though the military had disabled the alarm before I got the car. Disconnected it and the problem stopped.
DO NOT put a multimeter set to mA from + to earth, unless you want to see how quickly your multimeter blows a fuse.
Instead the multimeter needs to be in series with the battery +. ie remove the clamp from the + terminal and connect one meter lead to the clamp, the other to the battery +.
I would also suggest using the AMPS range before trying mA, in case the current is greater than the mA range can handle.
totally agree. also depends if it is a digital or analogue meter, ie. which way you connect it. if digital it may read - A instead of +A. If analogue and the range set is too low could break the meter if it goes 'backwards'.
Not really - just the standard RR alarm (doors, bonnet, tailgate) which were disabled when I bought the car (ex-SAS). I assume they disabled it as the risk of the car shouting its head off when on undercover surveillance duties was too high. There was a master lighting switch on the dash which disabled all interior and exterior lighting as well.
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