Battery Drain Thread

[peezen]

I finally had my GM rebuilt to solve my parasitic drain and unfortunately it didn’t.

My first question is about the trunk lights. I have the car on a trickle charger, and the trunk has been open for a few hours now but the lights have not gone off.

Are they not supposed to go off? Is the trickle charge keeping it awake? Is this finally the source of my battery drain?

Thoughts?

[rjjablo]

Supposed to go out after 16ish minutes. I would start there.

After that You hook up multimeter and measure drain. Once you establish that you start pulling fuzes to see when the drain drops and then start chasing that circuit

[shogun]

Perform Closed Current Draw Test
Maximum closed current by vehicle: E31 50mA, E32 50mA, E34 40mA, E36 30mA, E38 50mA, E39 40mA, E46 40mA, E52 50mA, E53 40mA, Z3 30mA

Performing Closed Current Draw Test
• Select proper measuring device (DISplus, MoDic or DVOM). Remember amperage draw in excess of 10A will damage DVOM.
-Use inductive amp probe of DISplus when amperage draw is high.
-When using DISplus inductive probe, clamp on negative battery cable with arrow pointing away from battery. Switch off all consumers.
-(It is not necessary to disconnect B- from body when using inductive probe)
• Connect (-) test lead to negative battery terminal and (+) test lead to a known good ground.
• Ensure all systems are OFF !
• Be sure DVOM is on and set in proper mode.
• Disconnect battery ground lead from body.
• Observe meter reading, wait 16 minutes for vehicle to enter sleep mode.
• Identify faulty circuit by disconnecting fuses, relays, control modules or connectors, observing meter readings.
• Defective circuit is found when current is below maximum closed current for vehicle being tested.

use this link for more details http://www.e38.org/battery.pdf

[peezen]

So I have narrowed a few things down.

1. the trunk light and glove box light do not turn off, and are on the same fuse.

2. the trunk doesn’t open unless the upper glove box is open.

3. the flashlight charger plug does not stayed plugged, harness is gone and two female ends aren’t tight enough.

4. when I touched the two ends of the flashlight charger together it blew a fuse

So I’m leaning towards the issue with the battery drain having to do with maybe the improperly wired flashlight charger not allowing the glove lights and this trunk lights to go to sleep?

Thoughts?

[EEDegreeToDrive]

So I have narrowed a few things down.

1. the trunk light and glove box light do not turn off, and are on the same fuse.

2. the trunk doesn’t open unless the upper glove box is open.

3. the flashlight charger plug does not stayed plugged, harness is gone and two female ends aren’t tight enough.

4. when I touched the two ends of the flashlight charger together it blew a fuse

So I’m leaning towards the issue with the battery drain having to do with maybe the improperly wired flashlight charger not allowing the glove lights and this trunk lights to go to sleep?

Thoughts?

First off, Locking the glove box is supposed to disable the trunk from opening (valet mode, the 'valet' key won't open the glove box or trunk). (Perhaps someone mixed up the wires for the glove box light/glove box key sensor and/or flashlight connector. )

Trunk light/dome light, etc. are supposed to go off 16 minutes after closing the doors. If that's not happening, your GM is not putting the car to sleep.
Did I do the module repair, or someone else?

If your GM is from a different car (used, etc), and/or not coded to your own car's options, it'll have trouble sleeping.
Missing Wiper relays and/or wipers not returning home can prevent the GM from sleeping.

[peezen]

Hey EE!

Yes I sent my GM to you to repair I know that the flashlight charger harness was snipped so I put two female connectors on them to connect it. Does it need to be wired a certain way with the two wires? Maybe that’s the problem.

I am at lose. I left the glove box open the other day to test it and the light stayed on all night.

[EEDegreeToDrive]

Hey EE!

Yes I sent my GM to you to repair I know that the flashlight charger harness was snipped so I put two female connectors on them to connect it. Does it need to be wired a certain way with the two wires? Maybe that’s the problem.

I am at lose. I left the glove box open the other day to test it and the light stayed on all night.

Go find the ETM, and examine the relevant sections.

6100.0 has the Glove box locking switch informing the GM if the glove box is locked.
6332.0 shows the interior accessories. double check the colors of the wires
etm3.png
etm2.pngetm1.png

[peezen]

It Looks like the flashlight charger could have been plugged in backwards, and maybe the glove light if that matters as well. I wonder if either of the K72(3) relays could be the problem.

[EEDegreeToDrive]

It Looks like the flashlight charger could have been plugged in backwards, and maybe the glove light if that matters as well. I wonder if either of the K72(3) relays could be the problem.

It seems like your glove box switches and/or lights and/or 'charging socket' wires might have been mixed up, perhaps once upon a time when someone had the dash out.
You should be able to study the colors and ohm out certain wires to ground to see what's up.
According to the ETM screenshots I posted,
X495 is the common ground for the glove box switches, and the charging socket. X779, charging socket + should have power all the time. The glove box light bulb should have power when the Consumer cut out relays in the trunk are 'ON' and should have nothing if you pull the relays (which will also disable the interior lights)

[peezen]

So I finally got around to doing this. Here is what happened: there are three other plugs in the glove box harness that are the exact same. Two go to microswitches on each door to activate the light when opened, and the third runs to the lock. I had plugged the lock harness into a door micro switch!

All is good now and the trunk lock works without having to open the glove box door now

As for the battery drain issue, I have had the GM rebuilt already, and have just ordered two new consumer cut off relays (61368353447). Hopefully this will solve the problem. I will report back once they have arrived.

Any further tips are always appreciated!

[peezen]

Ok so here is another update and some advice would be appreciated

I have had the GM serviced, and I just replaced both consumer cut off relays with brand new ones.

When I pop the trunk and leave it open the light will stay on forever. Locked car or not, the trunk lights do not turn off.

So where do I go from here? The glove box wiring is all sorted out.

Still have the battery drain

[sshivaram]

is the light ON if you close the trunk ? (keep phone inside in video recording)

[peezen]

I’ll give it a check and report back. Even if it down for off doesn’t the car stay ‘awake’ if the consumer cut off doesn’t put it to sleep?

[sshivaram]

My car's trunk video, car was powered off. The lights should go off when you close the trunk:
https://www.facebook.com/10000226096...2538292164830/

My car is perfect - super clean now, mechanically and electrically. Will check stuff , see how it should work and report back !

[peezen]

Yes, the trunk lights turn off when I close the trunk. That’s good news

[EEDegreeToDrive]

Yes, the trunk lights turn off when I close the trunk. That’s good news

That's not 'good news', the trunk switch is wired in series w/ the lights, so it has no bearing on sleeping.

As I said in a previous message, your interior lights and trunk lights are powered by a circuit that should go off when the car goes to sleep(16 minutes after closing the last door).

The 'switch' on the trunk light is just that, a simple normally closed switch. If your trunk is open the lights should go out after 16 min; If they're not, then your car is not going to sleep. (or something else is immediately waking it).

Find someone w/ INPA that can scan the general module and do a live view of all the inputs (door pins, micro switches, etc)

If you see any very strange errors logged in your GM, you might have a corrupted EEPROM/coding.

[sshivaram]

...so it has no bearing on sleeping....

Intent here was to make sure that light switches off , unrelated to sleeping.

So, after 15 mins, even when car is not powered, when one opens the trunk, that light should go off. Its not happening in your case.

is the car going to sleep at all ? Do you have access to a clamp meter to measure current flow from the battery terminals (loop it around negative terminal in the trunk, just one side is fine)? After 20 mins, go check if the clamp meter shows current flow. You should see readings of 0.05A when car is not sleeping, and sometimes it hits higher. In a sleeping car, the clamp meter shows 0.0A (can't even detect 10 milliAmp).

[CD05001CIA]

Intent here was to make sure that light switches off , unrelated to sleeping.

So, after 15 mins, even when car is not powered, when one opens the trunk, that light should go off. Its not happening in your case.

is the car going to sleep at all ? Do you have access to a clamp meter to measure current flow from the battery terminals (loop it around negative terminal in the trunk, just one side is fine)? After 20 mins, go check if the clamp meter shows current flow. You should see readings of 0.05A when car is not sleeping, and sometimes it hits higher. In a sleeping car, the clamp meter shows 0.0A (can't even detect 10 milliAmp).

Use a more sensitive meter. Sleep current is in the range of about 50 milli-amps, 0.050 Amperes. Can't detect 10 milliamps ... something wrong with your method of test...

loop sensing meter vs in line meter measuring current directly. "you know metallurgy..." This is starting to feel like a critical design review of SSHIV's proposals.

[sshivaram]

Use a more sensitive meter. Sleep current is in the range of about 50 milli-amps, 0.050 Amperes. Can't detect 10 milliamps ... something wrong with your method of test...

loop sensing meter vs in line meter measuring current directly. "you know metallurgy..." This is starting to feel like a critical design review of SSHIV's proposals.

The clamp meter is very sensitive. It can detect as low as 2 milli Amps, thats 0.002 Amp. I said when my car is sleeping, it "can't even detect 10 milli Amp" -- that means the car is truly sleeping, no current is flowing out of the battery.

Don't use a line meter here -- you have to hook it up inline, and it may blow up your meter if the battery current is spiking. Most traditional multimeters we see around can measure current of max 200-500mA. Avoid.

We are just trying to see if clamp meter shows 0 vs non-zero. It must show 0.

[Timm]

Normal sleeping current IS 50 milliamps - in the 16 minute period before it goes to sleep currents in the order of 500mA will be seen - and more. A DC clamp meter is pretty useless for measuring closed-current, too much drift, which is probably why you are seeing zero current demand, or you are measuring current in the wrong place (there is no sensible way to measure the current if both batteries are still connected).

All explained (including the proper way to measure the current) here:

[sshivaram]

(there is no sensible way to measure the current if both batteries are still connected).
]

I beg to differ, here is the clamp meter showing exactly how the current spikes happen.
At 0:17, i turn the key towards Run (when you hear multiple beeps since car door was open), and at 0:42, i turn off the key completely, and car is now in the 15 min window towards sleep.
Enjoy !
https://www.facebook.com/10000226096...0415924710400/

This clamp meter is very sensitive, and works pretty accurately. You clamp to the negative terminal of one battery, and you have to double the readings for two batteries connected in parallel.

I have used it to measure the 2-3 milliAmps flowing in the ignition wires also, very helpful !

[Timm]

This is why you are getting erroneous readings - with two batteries in parallel they share the current demand - and not necessarily evenly, you have no idea what the current in the whole system is because you are measuring at just a portion of it. By disconnecting ONE battery and measuring the current in the other battery cable you have a chance - but very little with a DC clamp meter.

DC clamp meters are also known to drift, they should be zeroed in the position where they measure the current - and that is impossible to do with a constant current in the cable you are measuring.

Here's what the true current demand is during the countdown showing currents around 0.5A - 0.6A during the 16 minutes and then around 50 milliamps after 16 minutes. These are the currents you would expect to see on a working system:

[CD05001CIA]

This is why you are getting erroneous readings - with two batteries in parallel they share the current demand - and not necessarily evenly, you have no idea what the current in the whole system is because you are measuring at just a portion of it. By disconnecting ONE battery and measuring the current in the other battery cable you have a chance - but very little with a DC clamp meter.

DC clamp meters are also known to drift, they should be zeroed in the position where they measure the current - and that is impossible to do with a constant current in the cable you are measuring.

Here's what the true current demand is during the countdown showing currents around 0.5A - 0.6A during the 16 minutes and then around 50 milliamps after 16 minutes. These are the currents you would expect to see on a working system:

Go Timm Go ! ! ! ! ! The Meek-ster from across the pond is correct. Pass Go, collect 200 dollars.

Go Dawg Go! (see pic). 'cause I don't know

S tow H igh I n T ransit.

Really I don't. {Timm, I tried to tell him...}

GoDog.jpg

[sshivaram]

OP has an issue, we are not looking for precision math here. After 30mins, go check using a clamp meter, its a 0 or non-zero we are looking for. Simple ! Don't have to get into any more complicated math lol.
I showed my readings, and my car is perfect, and use it as guidance.
Hooking up an inline meter is hard - i don't know where we can get one that reads 2-3 amps or more. During charging, nearly 5-6 amps are getting delivered to each battery at idle rpm.

Now, batteries in parallel, in theory, both batteries should discharge at the same rate. But due to different battery condition, they are very uneven. Again, it doesn't matter if one is discharging 0.3Amp and another is discharging at 0.15Amp, we are looking for zero vs non-zero in a clamp meter.

Happy Father's day all

[Timm]

Happy Fathers day too!

But, closed-circuit current on the E31 is 50mA - if you don't believe me you can trust BMW: https://www.meeknet.co.uk/E38/BMW_Battery.pdf#page=33