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[mc9]

Just checked my 2.5TD for quiescent battery current drain -- it's 200mA; way above thye 70mA recommended in the Battery Maintenance Guide.

This explains why the battery goes flat after a few days with the car idle.

I've checked the boot light -- it isn't on when it should be off.

Anyone have any "usual suspects" for this problem?

This car is a recent addition to the household, so I'm not that familiar with it.

Cheers

mc9

[hotel21]

[movedhere] Omega General Help [move by] hotel21.

[Dave DND]

I`d start with the power sounder on the alarm first

try disconnecting it and see what happens to the current

 :-/

[mc9]

This is curious.

Connected the DVM and recorded 200mA drain, as before.

Removed the fuses one by one to see what happened. No change until fuse 12.

Fuse 12 in place, all doors shut -- 200mA as before
Fuse 12 in place, door open -- 1.15A, as expected with courtesy lights on
Fuse 12 out, door open, courtesy lights off, door light on -- 610mA
Fuse 12 out, all doors shut -- after short delay heating fan starts, 8 amps drawn (??!!)
Fuse 12 out, open a door -- fan stops, 610mA
Replaced fuse 12, door open -- 730mA, all doors closed 30mA (?)

So, pulling and reinserting fuse 12 has somehow "reset" something (accessory timer perhaps)? The quiescent current is now apparently 30mA.

Do I have a faulty timer? Or something else?

Haven't looked at the power sounder yet.

Cheers

mc9

[Dave DND]

It would depend how soon after doing something you took a measurement.

Personally, I would wait for 5 mins to allow thing to come to rest before taking a current reading.

[Kevin Wood]

There is an accessory timer relay that keeps the rear lighter socket amongst other things active for a few minutes after closing all the doors. This could account for the 200mA but no idea what was going on with the heater fan.

Power sounder is also sound advice. The batteries in these fail and conductive goo leaks out onto the PCB leading to shorts and excessive current drain.

Kevin

[philhoward]

200mA will be 2.4W - how much do the electric window switch lamps take?  They stay live for a while (or is it just until the door is closed?)

[mc9]

Interesting that philhoward should mention window switch lamps -- see later.

Removed the power sounder. It looks like it hasn't worked for a long time; has white deposits on the outside where something has leaked. Anyway it's history now. But, removing it didn't solve the battery power drain -- still seeing 200mA drain.

Upon further investigation, I think I've found another problem, but I need the opinion of you who are more familiar with these "modern" vehicles. (We generally run older less sophisticated vehicles in our family, as we're not kind to our cars.)

Th driver's door switch has an intermittent connection. Sometimes it doesn't make contact when the door is opened and closed. When this happens the window circuits and window switch lights remain active, and the alarm doesn't set. Question: could the permanantly active window circuits and switch lights cause a flat battery?

Unfortunately there's another problem. Even when the door switch does work, the alarm system apparently has a fault. When I lock the car, the alarm LED flashes at the faster rate before settling to the normal flash rate after 10 seconds. According to the handbook, the fast flash rate indicates an alarm fault.

Any ideas what the alarm fault might be, apart from obvious stuff like doors and windows not shut properly? (Could absense of power sounder cause this "fault".)

Thanks fo your help.

mc9

[mc9]

Don't know the wattage of the window switch bulbs but something between 0.5 to 1W sounds reasonable. I'm sure that these lamps have been been staying on (sometimes) after locking and leaving the car unused for several days. This would draw 200mA, enough to partially discharge the battery after a few days.

The alarm has a fault but I don't what it is yet. The bonnet switch is working. I've removed the power sounder. I now lock the car through the rear door without setting the alarm.

Hope the battery discharge problem goes away now.

Next: find the alarm fault and fix the door switch.

mc9