Electrical problem diagnosis

[morfis]

Hi folks,

went out to the bus this morning and it seems electricaly dead - central locking not working, opened with key, no lights on dash.

Did the same a week ago - new battery was available so dropped that in and it started ok, went out to shops, came back - two hours later it wouldn't start. Disconnected battery and left it on charge for a couple of hours before going away for a few days (not in the car). Yesterday  I reconnected the battery and it started fine.

Any suggestions on how to diagnose the problem would be appreciated.

oops , forgot model -  98 disco 1

[Evilgoat]

Pull out glowplug fuses, make sure that any heay consumers (Rear window heater, headlights etc) are off them put a meter in series with the battery, make sure its rated at least 20A and then pull fuses out till the drain goes away. Its possible its a leaky Diode in the alternator

[morfis]

Thanks. What would a typical normal drain current be (glowplug fuse removed, standard TDi wiring)?

[morfis]

Current drain with glowplug fuse removed, ignition off - 200mA  which doesn't seem excessive?

[J.D.]

At a guess I would say the diode pack on the back of your alternator is knackered mate.

[Evilgoat]

200ma sounds a little high to be honest, only things drawing current should be ECU battery backup (if it has one) Alarm and possibly radio, all should be in the <10ma range each. Some alarms in standby draw nanoamps.

Its not worryingly high but its enough to say, nail a battery in a few days. Pulle the feed to the battery off of the laternator and then see what happens.

[morfis]

Thanks for the suggestions.

I had disconnected the radio as well (because there is nonstandard wiring to nokia car kit on the same feed). Alarm is standard disco fit.

Will try the alternator feed today.