840 Parasitic Drain

[jolo]

Refurbished GM from Tom Carter. I notice the radio also has no power with the relays installed and the radio fuse under the hood is fine

[Wuffer]

What about the fuse on the back of the radio? Or the one in the amp in the trunk?
This thread may be of assistance: http://www.bimmerforums.com/forum/sh...ul-Relay-Guide

[jolo]

Thanks

[jolo]

I just pulled the refurbished GM and it was quite warm are pulling the car into the garage (the car was only running for two minutes, but had been driven earlier in the day). Is that normal? Hot Consumer Relays and GM. Barring a short in the circuit, sounds like a faulty GM.

[adwebinc]

jolo - I know this thread is a bit old, but did you ever resolve your issue? I am having the same exact issue with those consumer cut off relays staying very warm. The cut off does not happen after 16 minutes. i have also had my GM refurbished (by a reputable member from this forum) and have had my cluster refurbished as well.

What else could be causing both of those relays to continue receiving power and thinking that they are supposed to stay "active"?

[6speeder]

Hot consumer cutoff relays point to faulty GM caps in the general module. im willing to bet your getting hints of this thru the behavior of your windows. to test make sure both doors are closed and all 4 windows all the way up. disconnect batteries overnight enough time for caps to empty. the next day open both doors first, then connect passenger battery only, if the windows dont drop 1 inch INSTANTLY (and i do me instantly) when you connect the ground that "lag" tells you its the gm caps. If the module was not rebuilt correctly (cold solder joints) the caps dont make contact with the board when the module is cool, the heat from the current expands them but it takes a few secs hence the lag.

[adwebinc]

Hot consumer cutoff relays point to faulty GM caps in the general module. im willing to bet your getting hints of this thru the behavior of your windows. to test make sure both doors are closed and all 4 windows all the way up. disconnect batteries overnight enough time for caps to empty. the next day open both doors first, then connect passenger battery only, if the windows dont drop 1 inch INSTANTLY (and i do me instantly) when you connect the ground that "lag" tells you its the gm caps. If the module was not rebuilt correctly (cold solder joints) the caps dont make contact with the board when the module is cool, the heat from the current expands them but it takes a few secs hence the lag.

Ok, thank you for the suggestion. I will try that tonight. I would be surprised though as the GM was rebuilt by someone here on the forum who has done quite a few and seems to really know his stuff.

[EEDegreeToDrive]

jolo - I know this thread is a bit old, but did you ever resolve your issue? I am having the same exact issue with those consumer cut off relays staying very warm. The cut off does not happen after 16 minutes. i have also had my GM refurbished (by a reputable member from this forum) and have had my cluster refurbished as well.

What else could be causing both of those relays to continue receiving power and thinking that they are supposed to stay "active"?

If the cut out relays are staying on, then the GM isn't putting them to sleep--

Check out this thread that I was working on recently:
https://www.bimmerforums.com/forum/s...-Bench-Testing

Make sure your wiper relays are in place.
Before your GM rebuild, did you have any trouble with the door modules? (things not unlocking/disarming properly?)

Was it me that rebuilt your module? If so, I'd be happy to take another look at it.

Hot consumer cutoff relays point to faulty GM caps in the general module. im willing to bet your getting hints of this thru the behavior of your windows. to test make sure both doors are closed and all 4 windows all the way up. disconnect batteries overnight enough time for caps to empty. the next day open both doors first, then connect passenger battery only, if the windows dont drop 1 inch INSTANTLY (and i do me instantly) when you connect the ground that "lag" tells you its the gm caps. If the module was not rebuilt correctly (cold solder joints) the caps dont make contact with the board when the module is cool, the heat from the current expands them but it takes a few secs hence the lag.

1) GM doesn't care if your windows are all the way up
2) GM and other systems in the car only need a few seconds to discharge, leaving them overnight doesn't add anything constructive, except allows hot relays to cool.
3) Your explanation of cold solder joints seems a little strange.. If the capacitors don't make contact there wouldn't be any heat from "current" because there would be no current. Of course, power isn't flowing "through" the capacitors anyway, so I'm not sure where you were going with that..

FYI-- There is usually a quick delay in BMW general modules since they are embedded computers that needs time to boot, query other modules, and start executing code.

Most GM failures are from bad capacitors that lose capacitance over the years.. The bad capacitors fail to smooth out spikes/drops in system voltage, so operating certain motors/relays/etc results in local brownouts, and cause the module to do a reboot. The ~1-2 second boot time, coupled with the condition that triggers a brownout results in the ~2 second cycling of relays when the battery starts to get low.

[adwebinc]

Hey EE - yes it was you that rebuilt my GM .

I have had no issues with the windows, door locks, etc. before and after the module rebuild.

Wiper relays are in place as well.

I did have the car in the shop for a couple of weeks getting the upper pan gasket replaced. So, I've got it ok the charger and I will make sure they batteries are fully charged and I will test everything again including the batteries.

Just read through your very thorough post that you linked above. Haven't looked at the prices yet, but would it make sense to replace all three of the wiper relays? Easy swap and assuming they aren't priced like the headlight relays shouldn't be too crazy cost wise.



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[adwebinc]

If the cut out relays are staying on, then the GM isn't putting them to sleep--

Check out this thread that I was working on recently:
https://www.bimmerforums.com/forum/s...-Bench-Testing

Make sure your wiper relays are in place.
Before your GM rebuild, did you have any trouble with the door modules? (things not unlocking/disarming properly?)

Was it me that rebuilt your module? If so, I'd be happy to take another look at it.


1) GM doesn't care if your windows are all the way up
2) GM and other systems in the car only need a few seconds to discharge, leaving them overnight doesn't add anything constructive, except allows hot relays to cool.
3) Your explanation of cold solder joints seems a little strange.. If the capacitors don't make contact there wouldn't be any heat from "current" because there would be no current. Of course, power isn't flowing "through" the capacitors anyway, so I'm not sure where you were going with that..

FYI-- There is usually a quick delay in BMW general modules since they are embedded computers that needs time to boot, query other modules, and start executing code.

Most GM failures are from bad capacitors that lose capacitance over the years.. The bad capacitors fail to smooth out spikes/drops in system voltage, so operating certain motors/relays/etc results in local brownouts, and cause the module to do a reboot. The ~1-2 second boot time, coupled with the condition that triggers a brownout results in the ~2 second cycling of relays when the battery starts to get low.

I went ahead and ordered 3 new wiper relays. Mine appear to still be the original blue modules. At $12 each, its worth a shot. Other than that, not sure what to try next.


Sent from my iPhone using Tapatalk

[EEDegreeToDrive]

Hey EE - yes it was you that rebuilt my GM .

I have had no issues with the windows, door locks, etc. before and after the module rebuild.

Wiper relays are in place as well.

I did have the car in the shop for a couple of weeks getting the upper pan gasket replaced. So, I've got it ok the charger and I will make sure they batteries are fully charged and I will test everything again including the batteries.

Just read through your very thorough post that you linked above. Haven't looked at the prices yet, but would it make sense to replace all three of the wiper relays? Easy swap and assuming they aren't priced like the headlight relays shouldn't be too crazy cost wise.

I went ahead and ordered 3 new wiper relays. Mine appear to still be the original blue modules. At $12 each, its worth a shot. Other than that, not sure what to try next.

If your wipers work in Low speed and High speed, then the relays are probably fine.. It's just when they're removed for one reason or another that the GM gets upset.
If you send it back to me, I'd be happy to reexamine my work. It's not likely a cold solder joint since I use a solder station and a pretty good size tip, but there's a small chance there's a solder bridge somewhere. I've still got my module hanging down, so I could test yours in my car pretty easily if you got it to me in the next week or so.
Also, thanks to David for sending me a Relay Module, I should be able to make some progress on my bench test. If it turns out your module is bad for some other reason besides capacitors, Tom C just sold me a spare I could refurbish and get out to you. In any case, I have 2 'duds' on my shelf from the last year of repairs, so something else is going on with these modules! I'm tempted to replace/reflash the Serial EEPROM in them and retest in case there is problem saving faults leading to a failure to sleep.

[David9999999]

I'm interested to see what ends up solving adwebinc's problem. I'll finally be reading the modules in my car this weekend (got a computer with Windows XP so I can run the old programs with ADS interface). Will be posting screenshots and findings.