Total electrical failure - E39

[bison]

Today I was driving my 2000 E39 (130k-ish miles, auto) and started to notice odd electrical glitches. First the radio died, no sound and fading display. Then the dash warning lights started to illuminate, primarily the air bag and one that looks like a gear with an exclamation mark thru it. Then, over the next 30 minutes, all of the gauges (speedo, tach, gas, temp) would go to zero, then intermittently come back. Then the battery light started to flash, but just for a very brief moment. Then the tranny acted weird, I think it was stuck in a single gear. The engine was running fine thru this, but then abruptly all power was lost. The car would not turn over, and battery power appeared to be very low. Had to get it towed to my local mechanic.

I'm thinking some master computer?? Can't be the battery as the alternator would have taken the load. Can't be the alternator or the battery light would have been on. Any thoughts?

[whiskychaser]

Sounds like a charging problem and your car ran off the battery until it died. The battery tell tale can be misleading - it only needs a small voltage to turn it off. The fact it is off doesn't mean the alternator is working perfectly. For safety reasons, there is a pecking order of which systems get power. The engine provides brake and steering assistance so that is last man standing. Not sure which alternator you have but you may get away with a new regulator/brush pack and charging the battery. Post the outcome when you hear from your mechanic

[632 Regal]

I'm going to bet a bad ground or cracked battery cable fuse.

[bison]

I'm going to bet a bad ground or cracked battery cable fuse.

I should have taken that bet... it was a bad alternator. Local indie fixed it today - $950. Ouch. $630 for the part alone.

[632 Regal]

I should have taken that bet... it was a bad alternator. Local indie fixed it today - $950. Ouch. $630 for the part alone.

My bad, was hoping a simple fix for you.

$630 for the part??? $320 labor too? That's just crazy since you can get the alternator under $200 all day long.

At least your car is good to go now.

[whiskychaser]

I imagine you have the same M54 engine as I do? Bosch regulator/brush pack is about $30 online and I would think it is worth a punt. You do have to remove the air filter box though ;-) But as Regal says, at least you are good to go now.