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[scottambrose]

so say i find its fuse 7 which is interior lights etc according to the book. do i then take each bulb out and put the ameter in each one to see which is drawing current

[allen25]

If you have been through the system and have found an offending circuit, do post up the results because almost certainly someone here will have seen it before.

[Martian]

so say i find its fuse 7 which is interior lights etc according to the book. do i then take each bulb out and put the ameter in each one to see which is drawing current

If the lamp is drawing current then it will be lit, although I'm now thinking (based on your choice of words) that the boot lamp switch could well be faulty and keeping the boot lamp illuminated even when the boot (or tailgate) is closed.
Although it's only a 5W load, that (combined with the normal quiescent drain you would expect) would be enough to drain the battery enough for it to notice if you don't use the car for a couple of days.

As far as the ammeter goes, you leave that in position of the fuse and you simply disconnect the devices on that circuit (eg, clock, radio, etc) until the current drain drops back to the expected norm.
When the current drain returns to normal, you have found the offending item.

[Entwood]

for the sake of a few quid it is well worth having one of these in your toolbox .... makes circuit checking a doddle .. they do different sizes for normal spades and micro-spades ...

http://www.ebay.co.uk/itm/Automotive-Current-Tester-STANDARD-Car-Fuse-Boxe-Test-/260597798106?pt=UK_Sound_Vision_Other&hash=item3cacd6d4da

hth

[scottambrose]

i pulled the rear seat down with the car locked and boot shut and the boot light was off. unless its coming on intermitantly. as when i checked last night i had no current draw from fuse 7.

[scottambrose]

fuse 7 is drawing 26.2 on my multimeter whereas all the others in the bottom row are reading 0. is that about right?

[scottambrose]

when i plug the meter into the cig light fuse, it reads 0 until i turn the key then it reads the same as fuse 7.
all i can see that stops working when fuse 7 is pulled is the kerb lights. is there anything else on fuse 7's circuit, and should fuse 7 have a permanant current even when the cars been asleep for over an hour

[scottambrose]

sorry to keep asking fuse 12 is also drawing 25 and fuse 20 is drawing .4. ive left fuse 7 disconnected but cant disconnect 12 as the info display and climate control doesnt work, what else does 20 use.

[Kevin Wood]

Can you include the units in your current measurements? 25A is a shedload, 0.4A is significant, 25mA is not a problem and 0.4mA is nothing at all for practical purposes.

[scottambrose]

http://www.toolstation.com/images/library/stock/webbig/98689.jpg?rand=576444555

this is the multi meter and ive set it to the 200 on the right hand side next to the v

[Dave DND]

I don`t like to be the bearer of bad news, but I doubt very much if that multimeter is going to be sensitive enough, nor adequate to start tracing miniscule current drain amounts. Great for general purpose voltage work, but you really ought to be looking at a clamp meter if trying to trace current drain.

 

[Kevin Wood]

You've got to spend significant money on a clamp meter to look at currents this small without it drifting all over the place, though. (let's face it, you can't get any DC clamp meter worth having for less than £60-75). Not worth it to fix one fault.

That meter will do the job but you need to know what range you're on and how to interpret the readings.

[opelman]

thought it was my stereo which was turning itself on in the night but ive disconnected that aswell as the power sounder and the boot light. and still i keep getting a flat battery every few weeks. ive changed the battery for 3 different types. and all tested good each time, are there any other common drains on the omega it could b?

I had the same problem on my -96 omega 2.5v6, it turned out to be wrong in the electrical box to the sunroof.

[scottambrose]

as i work at a motor factors ive charged the battery to 100per cent and tested and its come up ok. so i put it on ansd tested again on our tester and the reading this morning is axactly the same within .1 of a volt to last night. so the drain must be intermittant, i also tested the drain with the multimeter in series, on two of our vans and that read the same as on my car at 25. think i will keep testing the battery every few days and see how much it drops

[Andy H]

http://www.toolstation.com/images/library/stock/webbig/98689.jpg?rand=576444555

this is the multi meter and ive set it to the 200 on the right hand side next to the v

That looks like the 200 Volt AC range . You need to be reading using one of the 'A' (Ampere) scales.

The trouble with using a hobby meter to measure current in a car is that when things are switched on the current can exceed 10 Amps but as things shut down the current should drop to a few milliamps. If you use the 10A range (using the 10A connection) you won't be able to read currents below about 10 milliamps (depending on how many digits on the display).

If you connect the leads to the 'normal' connections on the meter (ie not the 10A connection) as soon as the current exceeds about 250 milliamps the fuse blows inside the meter.

Small Print.......
Hobby multimeters will tend to show a reading if used to measure DC voltage while switched to the AC voltage range (but with a fudge factor of square root of 2 to give an approximate RMS voltage).