Dead battery = cluster problems?

[JimLev]

What does your battery read if measured at the battery with a volt meter?
If you don't have one go to an autoparts store, they will read and test the battery for you.

[fuzzy530i]

"Well charged the battery over night, fresh off the charger it read 13.3, 30 minutes later it read 12.92, and then 3 hours later it was 12.86. Plugged it back into the car, right before I started the car it read 10V on the cluster, started it and it went to 11 then 13.4. After I shut off the car the battery read 12.4. No changes in the cluster or the clock on the radio."

The 13.3, 12.92, 12.86 and then the 12.4 after I shut down the car were all at the battery with a voltmeter. Most of the readings I've said have been voltmeter unless I referenced the test 9. And I hope the battery is good, it's only a couple days old.

[geargrinder]

Dropping to 10V at startup, thats something wrong. Not sure I even like the dropping ~1/2 volt in 4 hours when not connected to anything but that could be temperature influenced or something.

Either something is draining major juice, or you've got a bad connection (grounds someplace?) either one not allowing full voltage to get through.

Isn't electrical troubleshooting super fun?

[JimLev]

Dropping to 10V at startup, thats something wrong.

Isn't electrical troubleshooting super fun?

Sure, I like it, think you do to GG.

The surface charge will deplete on it's own after the charger is removed.
Dropping into the high 10v range while cranking should be OK.
I'd go back to where you bought the battery and have them do a real load test on it.
You could leave your headlights on for 5 min (eng off) and see if the voltage stays above 12.0v, if it doesn't the battery isn't holding a good charge.
Dropping down to 12.4 just after shutting it off isn't that great.
My 10 year old battery will read 12.4-12.5 after the car hasn't been started for 2-3 days.

[Chedley]

So I am curious: where did you buy your "couple days old" battery ? Are you sure it is a new, not a rebuilt used battery ??
If it is still under warranty, I will take it back and ask for another one or refund.

[fuzzy530i]

The drop to 10V was on start up right when I connected it after letting it go to sleep and disconnecting, figured it was just slow to adjust. I bought it from oreillys, they said new not refurbished but wouldn't surprise me if they were wrong.

Saw a thread where a guy said to pull fuses 18, 24, and 40 in the glove box, turn to position 1, and put back in. That worked on the coolant gauge for about 10 seconds, then it pegged red. Also made my airbag light come on.

[blackknight530i]

The drop to 10V was on start up right when I connected it after letting it go to sleep and disconnecting, figured it was just slow to adjust. I bought it from oreillys, they said new not refurbished but wouldn't surprise me if they were wrong.

Saw a thread where a guy said to pull fuses 18, 24, and 40 in the glove box, turn to position 1, and put back in. That worked on the coolant gauge for about 10 seconds, then it pegged red. Also made my airbag light come on.

edjack suggested it early on in this thread, but do the battery nap process. It involves waiting for the car to go to sleep (about 16 minutes), with the trunk open of course, disconnecting the battery for about 20-30 mins), then reconnecting. I've seen the weird gauge thing happen many times when the battery depletes really low while the car is on. I'm 95% sure it will fix your gauge issue, unless you're issue is actually with the DME plugs being wet.

Good luck and Go Tigers! (Clemson alumni here )

[fuzzy530i]

I tried that the last time I charged the battery and it did not work. I'm going to take it back to the store and make sure it reads good first but then I'll try it again, when you say DME plugs you're referring to the ones in the white box under passenger side cabin air filter?

Also I unfortunately don't have the pleasure of being there anymore, I graduated in may.

[blackknight530i]

I tried that the last time I charged the battery and it did not work. I'm going to take it back to the store and make sure it reads good first but then I'll try it again, when you say DME plugs you're referring to the ones in the white box under passenger side cabin air filter?

Also I unfortunately don't have the pleasure of being there anymore, I graduated in may.

Yes, plugs that go to the DME in the ebox under the passenger side cabin air filter.

I graduated in 12/2008. Always a Tiger though.

Sent from my SM-G965U using Tapatalk

[geargrinder]

Yeah from reading between lines sounds like the car has been no-battery for long periods repeatedly already so I suspect that avenue is well assplored...

[JimLev]

Being a southern car your ground strap from the pass side engine mount to the chassis is probably OK but may be worth checking just to make sure it's not corroded.

My son will be at the Clemson game this Sat. He got me this after he graduated.
image.jpg

[blackknight530i]

Being a southern car your ground strap from the pass side engine mount to the chassis is probably OK but may be worth checking just to make sure it's not corroded.

My son will be at the Clemson game this Sat. He got me this after he graduated.
image.jpg

My money will be going to Clemson University for a long time. No kids, just me.

Sent from my SM-G965U using Tapatalk

[fuzzy530i]

The battery and alternator tested good. I'll check the ground strap and DME connector tomorrow. I'm not entirely sure how that connector would've gotten wet all the sudden.

If it does end up coming down to me removing the cluster to check it out is there anything in specific I need to be looking at? Also after trying the fuse trick last night the temp gauge works for about 10 seconds and then the brake light comes on and the gauge pegs. Does that more than likely mean that the sensor is working properly?

[JimLev]

If you let the car go to sleep then disconnect the battery for 10 min, while the battery is disconnected turn the ignition key on to position 2 for a few min, then the key off.
Reconnect the battery, that should fix the temp gauge issue unless the cluster is got serious issues.
Is your SRS light still on?

[fuzzy530i]

I will try that, and yes it is.

[fuzzy530i]

JimLev, I owe you a drink of your choice! That fixed everything except the airbag light! Thank you so much!!

[fuzzy530i]

So unfortunately I woke up to go to work this morning and it was back to not working. Running voltage at the battery was 13.8 and 12.8 with key off. I also noticed yesterday that each time I started the car the clock would be about an hour and change off (early) from what it should be.

[JimLev]

Guess I should have jumped on the free drink yesterday, LOL.
You may have a bad ignition switch, just a guess. It has about 9 contacts in it.
At least now you know how to reset the system.

As for the airbag light you need an airbag reset tool to turn the light off.
I have a B800 that I got on eBay for less than $20. I haven't used it on my car, but have used it on a few other E39's that had the light on.
I see there is a newer model that is also being sold now, B808.

https://www.ebay.com/i/153102621743?...e04b40ffd96dad

Good Clemson win last night.

[geargrinder]

Yeah and if you have a general BMW proprietary scan tool it can usually reset the light too. Assuming theres no other problem.

I remain suspect that there's a major wiring problem someplace causing all this. Ig switch ? Maybe. Normally ig switch problems aren't this crazy. Battery voltage is clearly OK. More ground problems? Some failed module putting crazy voltage on a line that's not supposed to have juice on it?

[makenzie71]

Im going to suggest again checking the dme plug for water/coolant.

I’d also suggest testing every fuse for battery voltage with the car shut down.

[fuzzy530i]

I will look up how to test the ignition switch and check it out later in the week when I am done with finals. Makenzie71, when you say testing the fuses do you mean with a voltmeter or one of the things that just lights up when the fuse is good? Because I've done that, with just the light up tool, and they were all good.

So started the car after work and it wasn't working, but it started to work again as I made the turn into my neighborhood. Shut the car off and restarted it and everything was still working.

[JimLev]

You may want to unplug the temp sensor connector (engine off) to make sure the pins are clean.

[makenzie71]

I will look up how to test the ignition switch and check it out later in the week when I am done with finals. Makenzie71, when you say testing the fuses do you mean with a voltmeter or one of the things that just lights up when the fuse is good? Because I've done that, with just the light up tool, and they were all good.

So started the car after work and it wasn't working, but it started to work again as I made the turn into my neighborhood. Shut the car off and restarted it and everything was still working.

I mean check with a voltmeter and see which circuits are staying powered at all times.

[Chedley]

I still suspect a bad battery.
Can you replace the battery with a new fully charged battery, just to test the theory.

On my car, I have seen worse symptoms when the battery goes low. The old E39 is a known battery queen....

[fuzzy530i]

The battery has tested good, running voltage is 13.8X and with key off it is 12.8X. I doubt the parts store will swap it out when its testing good but if I run down all the other ideas and nothing fixes it I will try that.

With the clock issue and the cluster reverting to not working makes me lean towards GG's ideas, seems like something is stopping power to an important part or making it think it's not getting power/enough power. I'm going to double check the battery cables are tight, check all fuses, the coolant sensor, DME connection, and then the fuses under the passenger seat last and hope I find something wrong.