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Discussion Starter #1
Hi all!

I've got a fairly odd combination of electrical issues which have just sprung up. A few days ago, I started my 2001 330i vert (59,000 miles) for the first time in about 5-6 months (had to jump from another battery). Now:
  • The gauges on the dash (tach, speed, temp, and gas) are entirely unresponsive. However, three of the four still appear backlit when the headlights are on (the temp is no longer lit). Small dash display is entirely black. However, warning lights such as check engine and brake lights still work.
  • Turn signals don't work
  • A/C doesn't work although the climate control buttons and display are fully functional
  • The convertible top won't go down, although the little red light next to the top down button lights up as usual and I can hear clicking sounds from the back of the car which usually occur when the top is about to go down
  • The automatic adjustment of the right hand mirror when the car is put in reverse also no longer works, but the mirrors can still be adjusted normally
  • The nav display has gone black, but the screen itself is clearly on, it's just not displaying anything other than a black screen.
After some googling around, I figured that this was probably an instrument cluster issue, and resolved to remove the cluster and send it to Automotive Circuit Solutions for repair. However, I also noticed the battery was around 11.2 V even after driving the car for an hour or so, and the car would not start again after this drive (battery is 15 months old). Charged the battery overnight to 12.4 V and put it back in, then started up the car. While running, the voltage is only 12.1 V, far from the expected 14 V.

So, I'm wondering what could be causing this low voltage (alternator?), and if it's the lack of power which is causing the electronics to go haywire. Seems like a pretty extreme response to low voltage, but maybe possible.

Any help appreciated! I've been reading this forum regularly for 5 years now, so I'm almost excited to have some disaster to post about 馃槂

(note: The car's dash has had some minor issues for a couple years now. The small dashboard display screen has gone haywire before, and the airbag light dimly pulses on and off when the car is running. It seemed to me that these problems started when I jumped the car from another battery a couple years ago, although this could be coincidence.)
 

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2000 E46 323i, 3.0L and 2.0L Z3's
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Low voltages do some screwy stuff to the E46 which is a rolling computer. Getting your standing and running voltages right will be a big start.

I take it that the battery light is not up? This says that the alternator is charging. The low running voltage could due to the battery having a bad cell and the alternator is having a hard time pulling up the voltage. Get your battery load tested. If its good, then look at the alternator.

Do you have a good scanner that can read all the computers in the car? If not beg, borrow or buy one. It will save you $ over the ownership of your car. Get all the codes read from all modules in the car. There are lightly lots of low voltage codes, but there may be other codes that will help you in getting the car fixed.

If you are going to buy a scanner, get a good scanner with BMW software. There are many options out there. Couple are the Foxwell NT530 with BMW software or the INPA software (free) on a laptop with the special leads (cheap). There are others too.
 

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Discussion Starter #3
Thanks for the info. Checked the battery and it was strong, replaced the alternator today and running voltage is back up to 14 so that seems to be solved. Dash issues are still persisting. All I can figure is that the alternator gave out and surged at the end, frying something in the instrument cluster...? I have a more standard OBDII sensor but I鈥檓 ordering the leads and downloading the software you mentioned so hopefully that sheds some light. Solution may still be to send the cluster away for repair.
 

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The alternator is fine. I doubt that it fried anything. Where was the car stored during its 鈥渢ime off鈥? Rodents love to eat the wiring insulation. I鈥檇 start by inspecting the wiring under the hood. I鈥檇 also pull the gauge cluster. It鈥檚 held in with 2 screws. Using the steering wheel adjuster set the steering wheel down all the way and out (towards the rear of the car) all the way. Pull the screws and pull the cluster out at the top. Then remove the connectors and clean both sides of all connectors with contact cleaner.


Also, where did you measure the voltage?
 
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