What is your residual current draw with everything off?

[FactBV]

I just disconnected one of the battery terminals and used my multi meter to measure current draw, between the lead and battery post (in series), with everything turned off, apart from the immobiliser, it reads 0.22 amps or 220 milli amps.....not good . I have an odd after-market alarm with an led that flashes like a disco light, I also need to look at the after market head unit. I think that it should be more like 10-15 milli volts.

My battery is discharging over a week or so to the point where the clock stops (mind you the racket that the clock makes, it might explain that, yes I know they all sound like that). It's easy to measure; does anyone know what the residual current draw on their car is with everything off. Just for reference, the interior light draws around 0.4 amps when I switch it on. It would be good to have a reality check to make sure that I have not got my scales mixed before I go any further.

[Hoover.]

can't tell you what all the meter readings should be...BUT after 3 years at eating approx 3 batteries /year it was diagnosed to door pressure pads not pushing the switch far enough to switch off... far enough to turn the light of, but not far enough to swicth the relay

[dnb]

Mine's 150mA. I think this is a bit on the high side, but can't find anything that is staying on that shouldn't.

[Argent]

Put a new aerial in the Griff recently and found that the TVR fitted one had a built in amp that was wired to be permanently on, doubt it was much of a drain though.

A.

[FactBV]

I think that the accepted wisdom is to then remove each fuse in turn and monitor the current draw to see which one has the most effect. Then, if there are multiple circuits on the one fuse you put an adapter on the multi meter leads with two spade type fitting, insert it into the fuse socket and then turn the various services on, in that fuse circuit and again monitor the current.

However, I am guessing that the radio will be on an in-line fuse behind the dash and I am not sure what fuse the aerial amp would be on. I wonder how you can disconnect the alarm / immobiliser to see what difference it makes? I need to do some more research.

[FactBV]

After a trip to Maplins, and armed with a few extra leads for my multi-meter, I had another go at the current drain problem.

I pulled the fuses one by one and monitored the draw from the battery. In summary, 0.05 amps came from the 'CDL & H Mirror' fused circuit, which also powers the immobiliser, and the remaining current draw came from the 'interior light and horn' fused circuit.

I disconnected the horn and interior light, with no change so I pushed the door pins in to see what relays were making a noise. These turned out to be the central locking controller under the dash and the courtesy light delay relay in the foot well, as you would expect. Plus, a larger long grey relay under the dash was also making a clicking noise. I haven't worked out what it is for yet but it looks like this.




By removing the two relays and controller and testing the current draw, while re-fitting them one by one, I think that I have found the problem.

Firstly, only check the residual current draw with the doors closed or the courtesy light delay relay and some of the other relays will be energised (which I did last night). However, I also found that when I closed the doors this time the residual current reduced to 0.04 amps(after the courtesy light delay relay releases)a considerable reduction, but then if I opened and closed the door again it would stay at 0.2 amps plus. Open and close the door again and the current stabilised back down to 0.04 amps and it alternates like that. It doesn't matter which door you open or close, the current draw goes from high to low on alternate door openings. As soon as I left out this long grey relay, it worked fine, every time. It is almost as if it is latching on alternate activations. Maybe it is just a fault or maybe there is some reason for this; maybe the central locking controller is part of the problem, but I don't know yet.

Anyway, I am almost there. It does prove that if you are working on your car in the garage for a few days, don't leave the doors open for extended period of time, even with the interior lights switched off as it will drain the battery 5 times as fast compared to when the doors are closed.

If anyone knows what this grey relay is with the big R on the front, please let me know.

[Discopotatoes]

Heated mirrors
See my thread
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
My symptoms were very similar, it turned out to be the alternator diode pack

[FactBV]

Discopotatoes said:

Heated mirrors
See my thread
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
My symptoms were very similar, it turned out to be the alternator diode pack

Thanks, really helpful. So it looks like the grey relay is for the heated mirrors. Also, I have been doing all the testing with out turning the ignition on and off, I will see what difference that makes. Interesting to see that the guy just removed the grey relay and it was all fine (I guess that you wouldn't have heated mirrors for that minute at start up, but is it the ice detector that switches on the mirrors after that or just a warning......more reading required.

I don't think that it is the diode pack, because without the mirror heat relay all is fine but as you say very similar symptoms. thanks again.

[Discopotatoes]

I may still have a small intermittent drain like you, but I need to eliminate the large alternator drain first.
This was my residual draw

Which like you alternated to this on opening and closing the doors

But then to this
So when my alternator is sorted ill be checking further.
If you find the culprit before me I'd be interested to know what it is.
I do know its not the curtesy light relay or light because I removed mine and still had the problem
An interesting read
http://www.diagnosticnews.com/featured/parasitic-b...

Edited by Discopotatoes on Monday 17th June 05:59

[FactBV]

Some good information in that article, I actually have one of those battery disconnects fitted and hadn't even thought about using it, so there is no break in the circuit when you change the flow through the meter.

In terms of the grey relay, it is used on the Ford Granada and Sierra for the heated rear screen, so it being used on our cars for the heated mirrors makes sense (maybe it is also used on the Fords for the heated mirrors but the guys at the Ford garage couldn't find reference to it). Maybe that is why it is a bit bigger for larger contacts.

The original part number is 88AG 18C641 AA (88 is the the year). However, this part number is not recognised by the modern Ford parts system and uses 6176490 which has also been replaced with 1387506. It's £90 from Ford, if they can find one So I have bought a second hand item. I will have a play today or tomorrow and let you know what I find.

[FactBV]

Been at it again this evening. I swapped over the large grey relay for another, same problem; high current draw then down to 0.04 amps on alternate openings of the door (either door it doesn't matter). It is not random, definitely alternate opening and closing of the door and you can hear the contacts in the grey relay sound as if they latch on the first door opening and closing and then release on the second, its a different noise.

Turned the ignition on and off, no difference. I also tried a new door / central locking / relay / module (whatever it is called) and no difference. In fact you can remove the courtesy light delay relay and the door controller and it still does it.

Perhaps they all do that and it is not a fault

I am not even sure that mine has heated mirrors and I am very unlikely to go out when I need heated mirrors so have just taken the relay out for the moment while I concentrate on my engine problems..............why do we do this

[Hoover.]

no idea... took me 4 years to find my battery drain issue, along with a bout 6 batteries fried (all free from from Halfords ) ... mine wasn't relay related though, mine was door pins switching of internal lights but not the relays which was fixed by larger rubbers pads at pin contact points on the doors...... I'd been pressing them in by hand when testing so all seemed good, it was Graham at Bespoke Performance who worked it out (4 different garages had previously no joy)

[Mr Jenks]

FactBV said:

In terms of the grey relay, it is used on the Ford Granada and Sierra for the heated rear screen, so it being used on our cars for the heated mirrors makes sense (maybe it is also used on the Fords for the heated mirrors but the guys at the Ford garage couldn't find reference to it). Maybe that is why it is a bit bigger for larger contacts.

Not sure about the larger contacts theory, I suspect that it also contains a timer circuit so the HRW/mirrors are only powered for around 10 - 15 minutes then switch off automatically.

[spend]

You have to wait 15mins for the timer to run off, turning the mirror heater off by opening the door didn't seem to deactivate the timer circuitry on mine. However my early car didn't activate any of the mirror circuits until the ignition was switched on...

[dnb]

The relay for the heated mirrors on mine was a through hole mount component in the heater control unit. Looks like they are all different...