Fx45 2004 Battery Drain from BCM

H

Harvey Munt

Member
Car
FX45 2004 awd
Name
Harvey
Hello to everyone..
So,,I have a problem with battery draining down if car left for a week or 2. I am hoping some of you may be able to verify if what i have found testing so far is normal or not on this model ?
When testing with an amp meter i have found my battery drain is 0.120A and found most of that is draining through the 50A fusible link in the under bonnet fuse box which i think feeds pin 55 on BCM.(Body Control Module).
I have found that one of the relays in the BCM circuit board is pulling in all the time causing this drain. When i connect the black connector to the Bcm you hear it and it stays all the time..I have also found the relay is getting its earth from the black wire on pin 52.
I have looked for a diagram and found that these pins 55 and 52 (Live and Earth) seem correct. But cannot believe that it is correct that a relay should stay live..
So wondering if anyone knows about this system and can confirm that their cars do the same or not?
With the BCM disconnected i have found the drain reduces to 0.003A which is more acceptable..Does anyone else hear a gentle click in the bcm when power put to it..?
Thanks For now ...
 
Harvey Munt said:
Hello to everyone..
So,,I have a problem with battery draining down if car left for a week or 2. I am hoping some of you may be able to verify if what i have found testing so far is normal or not on this model ?
When testing with an amp meter i have found my battery drain is 0.120A and found most of that is draining through the 50A fusible link in the under bonnet fuse box which i think feeds pin 55 on BCM.(Body Control Module).
I have found that one of the relays in the BCM circuit board is pulling in all the time causing this drain. When i connect the black connector to the Bcm you hear it and it stays all the time..I have also found the relay is getting its earth from the black wire on pin 52.
I have looked for a diagram and found that these pins 55 and 52 (Live and Earth) seem correct. But cannot believe that it is correct that a relay should stay live..
So wondering if anyone knows about this system and can confirm that their cars do the same or not?
With the BCM disconnected i have found the drain reduces to 0.003A which is more acceptable..Does anyone else hear a gentle click in the bcm when power put to it..?
Thanks For now ...
Click to expand...
Hey Harvey, this is good stuff! I've had a similar problem. I wish I could intelligently comment, but I don't know what or where that body control module is. Do you have a pic of it? Have you determined anything further since listing this?
 
I've read about these electrical gremlins on the G35 which has a similar setup to the FX. From what I've noticed, the common cause of these is due to water getting into filling up the battery tray area or water soaking up the electrical components in the footwells from bad/clogged sunroof drains. I experienced the former after a heavy rainstorm in my previous 2003 G35. Was surprised how much water/gunk I had to clean out of the battery tray. I left the lower tray bolt off so water could drain out when it rained heavily. Might be a good idea to check these out first. Other reasons I came across were bad grounds or the BCM itself. A lot more G35s were sold so try googling "G35 BCM" for more hits.
 
kahlilj said:
Hey Harvey, this is good stuff! I've had a similar problem. I wish I could intelligently comment, but I don't know what or where that body control module is. Do you have a pic of it? Have you determined anything further since listing this?
Click to expand...
Hey, thanks for your reply..
The bcm is situated in behind the left kick panel right near your pedals.
You would probably just about hear its gentle click through the panel if your ear was close when someone connected the battery.. But really need an amp meter connected to check current draw and see how much it drops to when resting.
It takes a few minutes for the modules to sleep after closing doors etc..
 
TheMole said:
I've read about these electrical gremlins on the G35 which has a similar setup to the FX. From what I've noticed, the common cause of these is due to water getting into filling up the battery tray area or water soaking up the electrical components in the footwells from bad/clogged sunroof drains. I experienced the former after a heavy rainstorm in my previous 2003 G35. Was surprised how much water/gunk I had to clean out of the battery tray. I left the lower tray bolt off so water could drain out when it rained heavily. Might be a good idea to check these out first. Other reasons I came across were bad grounds or the BCM itself. A lot more G35s were sold so try googling "G35 BCM" for more hits.
Click to expand...
 
Hi.
Thanks for your suggestions.
I don't think water ingredients water ingress is the reason as car lives under cover and in sunny Spain..
I will check the earths though.
And Google the more common G35.
 
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