The benefit of using French Mike's method is that you can safely get more accurate readings of current drain.

Start off with the meter set at 10 amps, then once you have confirmed the drain is down to milliamps, replace the positive terminal to the car's battery and reset the meter to milliamps and lift the positive clamp again to take the reading. :}

Finally got to run some tests
 

Many thanks for the inputs into this thread and specifically my question on how to test....

I set up the test removing the main battery feed and connected to the screw as described in the linked post. (I should say before doing this I opened up the cover on the sat nav and locked the car and yes the sat nav light was still glowing well after half an hour so that was my suspect)

When doing the test with the sat nav unit still connected I was getting .6 of an amp after about 10 minutes.... disconnected the sat nav and this was down to .15amps (still to high) after the same period of time.

Problem I've got and maybe I'm being dumb is how to change the meter to milliamps as I need to disconnect that then sets the alarm off (is there a fuse to pull to disable the alarm?) if so I suspect I could disconnect and then change the red lead socket to milliamps.

One other observation is when on my car the sat nav unit is disconnected the display on the hi-line unit is blank. The radio still works and the channels change on the buttons but I cant see to do anything else. However I've plugged the sat nav unit back in locked the car and now having plugged and unplugged the unit the light goes off when the car is locked !

So the main two questions to this great hive Rover 75 mind are

1. How long to leave the car locked with the multimeter on to see if it drops from .15 (150 ma) tothe suggested 30-50ma?
2. How to swap the meter probe sockets over to milliamps without the alarm going off (pull fuse if there is one ?) and just put the meter back on or does disconnecting the meter reset something so the car is back to putting out enough amps to blow the fuse in the milliamp part of the meter?

I hope some or all of that made sense ??

TIA Nev

On most meters once the 10 amp Range is selected it will automatically range down to any reading above 0 and the decimal place moves. Don’t lock the car as this will activate the alarm and then show current, unless your trying to show this? Just make sure your bonnet switch is pressed. Once the meter is connected remember you only have 10 amps of protection so actuating door locks could blow the meter fuse. We may need a picture or make and model of the meter your using as I’m not sure if you can upload photos being non subscribed

Here’s one I checked a while ago set at 10 amps. Sorry for the poor photo, it’s a screen shot from my twitter account

No, you are not being dumb. It's where my method scores - https://the75andztclub.co.uk/forum/s...w.google.co.uk

You loosen the fusebox link enough that it disconnects, with the meter wired in place of the link. Tightening shorts across the meter, which then allows you to swap from the 10amp range to the milliamp range, without disturbing the cars slumber. Basically, you use one of the bolts securing the link as a meter bypass switch.

You can get some idea of the circuit causing the discharge, by pulling fuses, but some will disturb the sleeping electronics so you start again.

Be aware, that my method ignores any discharge via the alternator and starter motor.

I got my problem discharge down to around 20mA after some hours spent tracing my problem - its a CDTi with the hi-line nav radio TV system replaced with one of the radioguy ones.

I don't think my meter ranges down - hopefully this is a pic of my testing set up getting the 150ma reading on the 10 amp setting ?

https://photos.app.goo.gl/AbihnHaPeVbVJhFG9

Thanks Harry for the reply... I have been using your method as per the photo in the reply above. So I think I have it now, I need to maintain the battery + to the (Blue sq) screw while removing the multimeter and swapping to the Milliamp socket and adjusting the switch position this will stop the car from sounding the alrm as I'll not be disturbing its slumber power !

Yes with either Harry's or French Mike's method you can take the meter out of the circuit whilst changing ranges and then take the reading. :}

hi, my battery is at 12.5V my voltmeter is showing 0.39 amps drainage, i don't have navigation TV, webasto(FBH) fuse is out, i heard it could be the glow plug relay i removed the 100amp fusaible link which some say its for the relay and it still reads 0.39, some say it could be the alternator is there a link for the alternator i can remove to test the reading then?