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-   -   Case study: Low-voltage dead instrument cluster - no alphanumerics & most gauges inop (http://www.bimmerfest.com/forums/showthread.php?t=568782)

bluebee 09-15-2011 11:01 PM

Case study: Low-voltage dead instrument cluster - no alphanumerics & most gauges inop
 
9 Attachment(s)
I haven't done the research yet to figure out what could possibly be happening; so allow me to simply report what happened today to my 2002 525i instrument cluster & MID:

SUMMARY:
  • DEAD:
    • All alphanumerics on the instrument cluster do not display
    • Clock on MID does not display
    • Fuel gauge is dead (see intermittent anomaly below)
    • Tachometer is dead
    • High beam blue display is dead
    • Almost all warning symbols appear to be dead (see exceptions below)
  • ALIVE:
    • MID display works for radio/CD/mode functions only
    • Speedometer needle works
    • Temperature gauge needle works
    • Manifold vacuum (i.e., fuel economy) gauge needle works
    • Green turn signal display & hazard light display both work
    • Back lighting works when I turn on the headlights
    • On the left side of the cluster, the red battery & red low oil level indicators work when turning key to position 1
    • On the right side of the cluster, two lights go on when I start the car (I don't remember which so I will snap a picture later of them)
  • INTERMITTENT:
    • The fuel gauge (which is at 3/4 tank) started working 15 miles into a 20-mile drive; but upon restarting the car for the 20 mile return drive, it stayed dead.
DETAILS:
  1. Cluster & MID displays were working fine.
  2. At home, I forgot to enter the mileage into my mileage log, so, I went back to the car for that data, and accidentally left the key in the ignition with the ignition on but the car not running (I don't remember if it was position one or two but certainly not three).
  3. Only a couple of hours later, I tried to start the car but it was completely dead (which is surprising after just a couple of hours since the headlights were not on).
  4. No indications of alternator/battery or FSU problems (but of course, I will check that in the debugging stage); battery is about five years old (will check voltage at the terminals).
  5. With the ignition key off, I put my 4-amp battery charger on the correct engine points and was surprised to see the amp meter needle pegged way past the 6-amp point.
    • I didn't snap a picture as I figured the battery, somehow, was just overly depleted and that it would go down to 4 amps soon.
  6. I left the charger on for about an hour, maybe two hours
  7. Upon starting the car, I tried to unlock the cluster to check alternator output, but was immediately startled by the lack of ANY alphanumeric display!
At this point, I've done zero research ... so I have to figure out how the cluster works in order to figure out WHY those particular items are dead and alive.

But, as always, pointers are welcome at this early stage in the debugging process!

http://www.bimmerfest.com/forums/att...1&d=1316155592

Vin M 09-16-2011 01:09 AM

I would start by checking the fuses first, the fuses for the instrument cluster should be located in the front fuse panel inside and above the glove compartment.

Also, try the famous passenger side sun visor light test and see if anything changes...you may have a bad ignition switch.

Although, the dead battery suggests either a charging issue, or the battery itself isn't holding sufficient charge anymore. How old is the battery?

If you can't check the voltage by unlocking the cluster, try the old fashioned way...with a volt meter at the terminals.

At idle it should read 13.5 volts.

Above idle it should be charging at 14.3 volts

If it drops below 14.2 volts (above idle) it might be an indication that there's a problem with the alternator keeping a consistent charge (maybe a bad regulator)...also, check the belt for the alternator as well.

The battery should hold a 12.6 volt charge when the car is off, however, that may drop considerably while cranking the engine over if it's weak.

poolman 09-16-2011 02:30 AM

Disconnect the battery from the car when charging it

moots 09-16-2011 04:18 AM

6amps is a lot to have had exposed to the electronics.batteries shud never ever be charged in situ due safety,in case the battery decides to explode.you just made it worse by not disconnecting the cables thereby subjecting the car's electronics to 6 amps pulses thruout the 2 hour duration.

i suggest you hook it up to a scanner to see if other modules are affected.the ike will surely show a host of faults.in your case your instrument cluster is fried and replacement is the only cure.

the clock on the mid is indirectly related to the cluster.whenever i disconnect the cluster,the clock display on the mid resets itself to 00:00.perhaps if you put in a new cluster the clock will come alive again.

good luck

Fudman 09-16-2011 04:57 AM

Quote:

Originally Posted by Vin M (Post 6321434)
I would start by checking the fuses first, the fuses for the instrument cluster should be located in the front fuse panel inside and above the glove compartment.

Also, try the famous passenger side sun visor light test and see if anything changes...you may have a bad ignition switch.

Although, the dead battery suggests either a charging issue, or the battery itself isn't holding sufficient charge anymore. How old is the battery?

If you can't check the voltage by unlocking the cluster, try the old fashioned way...with a volt meter at the terminals.

At idle it should read 13.5 volts.

Above idle it should be charging at 14.3 volts

If it drops below 14.2 volts (above idle) it might be an indication that there's a problem with the alternator keeping a consistent charge (maybe a bad regulator)...also, check the belt for the alternator as well.

The battery should hold a 12.6 volt charge when the car is off, however, that may drop considerably while cranking the engine over if it's weak.

BB:
+1, on checking both the fuses and battery. The fuse should have protected the cluster. And if this is your original BMW battery, you are overdue for replacement. If I remember correctly, you posted pictures of your battery (w/ a wrench) and it was white, which indicated it was a BMW abttery. I also recall your FSU thread. If your battery has died multiple times, it may have been weakened by your FSU experience. Look at these two things first. Good luck!

Flybot 09-16-2011 05:03 AM

Sorry to hear of this. Was the key ON or OFF when you hooked up the charger? I dont see how you could fry anything unless the key was in a position other than OFF when you hooked up the charger. Otherwise, I would look at doing a battery disconnect and reset. As the battery died with the power ON, the modules may have gone full retard with the low voltage situation.

doru 09-16-2011 05:45 AM

Sorry to hear, but did you disconnect the battery prior?

Steve D 09-16-2011 05:57 AM

I have charged my battery by connecting to the terminal under the hood scores of times over the past 10 years and never had any issues. I always have the ignition off and the key removed. I have never seen it draw more than 10A from my 15A charger even with a battery low enough that it won't start the engine. I have even inadvertently set the charger switch to 100A start position which pegged the ammeter with no problems.

My guess is that the transients (sparks) that occur when the charger cables are connected and disconnected somehow got into the electronics that were connected with the ignition switch in the on position. Most good electronic designs have transient protection built in so these protection devices may have did their job and clamped the transient and the resultant current surge just caused a fuse to blow so the electronics were protected. I agree that you should check all the fuses.

Good luck,

Steve D

dvsgene 09-16-2011 07:06 AM

Quote:

Originally Posted by Steve D (Post 6321585)
I have charged my battery by connecting to the terminal under the hood scores of times over the past 10 years and never had any issues. I always have the ignition off and the key removed. I have never seen it draw more than 10A from my 15A charger even with a battery low enough that it won't start the engine. I have even inadvertently set the charger switch to 100A start position which pegged the ammeter with no problems.

My guess is that the transients (sparks) that occur when the charger cables are connected and disconnected somehow got into the electronics that were connected with the ignition switch in the on position. Most good electronic designs have transient protection built in so these protection devices may have did their job and clamped the transient and the resultant current surge just caused a fuse to blow so the electronics were protected. I agree that you should check all the fuses.

+1 Charge my battery each month with 12A for 2 hrs for the past 5 years to keep it topped off. SO FAR, no such issues but I charge directly at the battery. Battery from Autozone is now going on 9 years. Check your fuses.

bmw_n00b13 09-16-2011 07:19 AM

10A is nothing; the alternator, depending on model, can output 120-140A, with the battery as the buffer. With the key in the on position, the car can draw 60A. A good coding-capable charger will be able to demonstrate that; maintaining 13.8V to the car while reading codes and testing modules I have seen the charger jump to 63A (capable of 70A). I agree that a dead battery shouldn't be charged in the car, but just as the battery is designed to absorb excess alternator output, it should absorb excess charger input (unless the charger is crap).

Hope you get the cluster back! Have you tried the gremlin removal process (disconnect battery)?

jygesq 09-16-2011 07:39 AM

try a reboot
 
Disconnect the battery leads from the battery. CAR SHOULD NOT BE RUNNING when you do this. THEN short them together for ten seconds . some people also turn on the ignition switch
while doing this. This drains any excess voltage from any modules. It cost nothing to try. It has fixed some instrument gremlins in my car (fuel indicator givng false readings)

QSilver7 09-16-2011 09:16 AM

When you charge the battery using the terminals in the engine bay...it is safer not only because of less chance for spare/explosion from the battery's off gases...but the front terminals are fused to help prevent damage from a spike or surge. And if I remember correctly...this is what Bluebee did, right? She didn't hook directly to the battery in the trunk.

Also...here's a tip...if you need to check your odometer...you don't need your key or have to turn the ignition on...just PRESS the left button on the instrument cluster and the odometer will illuminate for a few seconds to allow you to record the mileage...then turn off. :D

dvsgene 09-16-2011 09:18 AM

Quote:

Originally Posted by qsilver7 (Post 6321946)
also...here's a tip...if you need to check your odometer...you don't need your key or have to turn the ignition on...just press the left button on the instrument cluster and the odometer will illuminate for a few seconds to allow you to record the mileage...then turn off. :d

^^^^^this


And there is also the tip to wait for car goes to sleep (16mins) before charging or disconnecting battery (as a precaution)

bimmerteck 09-16-2011 01:09 PM

DC Amperage of the charger in this case has no bearing on the modules in the car. What VOLTAGE was the charger operating at and was it a clean DC current or was AC leaking through the charger while connected as well?


I have seen a failed voltage regulator fry electronics while it was outputting 20v DC and I have also seen as little as a few hundred milliamps of AC voltage leaked through a faulty charger brick an entire vehicle.

Check you charger carefully Bee and be sure to have it under load while doing so. ;)

Whorse 09-16-2011 02:20 PM

poor bluebee

bluebee 09-18-2011 11:08 PM

1 Attachment(s)
Quote:

Originally Posted by bimmerteck (Post 6322415)
Check you charger carefully Bee and be sure to have it under load while doing so.

One thing I've learned, is NEVER CHARGE THE BATTERY ON THE CAR!

Today, I took the battery out of the car to test it as per:
- How to test a BMW E39 battery & alternator

Certainly the battery is bad, so I'll replace it today, as per:
- Good Replacement Batteries for the e39?

And then I'll move on to the fuses, as per:
- Need help with location of the fuse boxs and overview of fuse positions for 528i?

Like when it was in the car, the 25-year-old battery charger was pegged at >6 amps for quite a while, at least a half hour, maybe 45 minutes, before it dropped back to 4 amps:
http://www.bimmerfest.com/forums/att...1&d=1316409294

The amp meter on the charger seems to be similar to that on the Fluke 75 so I think it really is pegged above.
http://www.bimmerfest.com/forums/att...1&d=1316412368

SlorpBop 09-19-2011 03:00 AM

Even though it doesn't help much at all I'll just say that I have charged and boosted more BMW's and E39's than I could possibly count after working at a BMW dealership for 4+ years as a lot attendant back when these cars were new. I have never seen this happening to ANY of our cars. I can only imagine that it might be a problem with the charger itself or some other serious anomaly. Anyway, I hope you can figure it out, and I'm sorry about the ****ty luck.

Edgy36-39 09-19-2011 05:12 AM

Really sorry to hear Blue. I hope its a fuse issue, or comes back after a battery disconnect.

bluebee 09-19-2011 05:59 AM

4 Attachment(s)
Quote:

Originally Posted by JimLev (Post 6326712)
was the charger voltage ever read?

It's still dark outside at 5:30 am but I just went outside to double check the charger current and voltage. The charger appears to be good (even though it was bought in 1982 so it certainly was meant for the older cars before sensitive electronics).

1. The charger open-circuit voltage is about 12 volts DC RMS with the battery out of the loop (which is roughly about 14 volts peak to peak full-wave-rectified at 120Hz based on oscilloscope engravings made in the 80's on the back of the charger).

http://www.bimmerfest.com/forums/att...1&d=1316436321

2. The charger closed circuit voltage, in parallel with that of the battery, is about 13 volts DC.
http://www.bimmerfest.com/forums/att...1&d=1316436484

3. The battery alone, without the charger, is about 11.4 volts (after being charged for 12 hours).
http://www.bimmerfest.com/forums/att...1&d=1316437978

4. The charge current (after 12 hours on the charger) is reading on the Fluke 75 DMM just about what the gauge on the charger is reading, at about 2 amps (so I think the gauge on the charger is reasonably accurate).
http://www.bimmerfest.com/forums/att...1&d=1316436459

There was one anomaly yesterday, but I'm not sure if I just accidentally changed the scale or if the charger has an intermittent so I can't conclude anything from that. The voltage on the Fluke across the battery while it was charging was off the scale ... but again ... it may have been user error.

I just now shook the charger while making these measurements, and they remained stable.

There is nothing in these measurements that shows any problem with the charger.

Fudman 09-19-2011 09:22 AM

Quote:

Originally Posted by bluebee (Post 6326794)
3. The battery alone, without the charger, is about 11.4 volts (after being charged for 12 hours).
http://www.bimmerfest.com/forums/att...1&d=1316437978

BB: This looks like you have a battery that is on its' last legs. Replacing it should resolve your problems (I hope).

champaign777 09-19-2011 09:42 AM

i hope you WAIT 15 MIN for car goes into SLEEP MODE BEFORE disconnect the battery

dvsgene 09-19-2011 09:44 AM

Quote:

Originally Posted by champaign777 (Post 6327183)
i hope you WAIT 15 MIN for car goes into SLEEP MODE BEFORE disconnect the battery

It's actually 16mins. :D

bimmerteck 09-19-2011 10:23 AM

Quote:

Originally Posted by bluebee (Post 6326562)
One thing I've learned, is NEVER CHARGE THE BATTERY ON THE CAR!

You are overreacting b/c you connected a solid state battery charger with a failed step down transformer to your car and possibly killed your battery and some control modules. ALL modern BMW's batteries are regularly connected to modern digital chargers while they are programmed no disconnection of the battery required.

Vin M 09-19-2011 11:03 PM

Quote:

Originally Posted by Fudman (Post 6327149)
BB: This looks like you have a battery that is on its' last legs. Replacing it should resolve your problems (I hope).

+1

11.4V after a 12 hour charge is definitely an indication the battery has seen better days.

bluebee 09-19-2011 11:28 PM

1 Attachment(s)
Good news! (audible sigh of relief!)

The seemingly complex & comprehensive cluster death (amazingly) was solved today (simply) by replacing the (bad) BMW battery!
- Pictorial discussion of charging, testing, removing, & replacing the BMW E39 battery

Here is a pic, taken today, as I breezed along highway 85 in San Jose. The tach & fuel gauge & alphanumerics were all suddenly back in operation!

Even the MID time display returned!

Whew!
http://www.bimmerfest.com/forums/att...1&d=1316499514

So the question becomes, WHY/HOW could a battery that suddenly (and without warning) "went bad" cause 'just' the following units to suddenly stop working completely?

- The tachometer was totally dead (speedo was fine)
- There were absolutely no alphanumerics on the cluster (and most indicator lights were also dead)
- The MID time alphanumerics were totally gone (but other alphanumerics were fine)
- The blue high beam indicator went inoperative (but turn indicators were fine)
- The gas gauge was inoperative most of the time (except for a brief interval in the middle, when it suddenly worked until I shut down the vehicle)


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