About to use my X as target practice
 

I am at the end of my rope with this BMW! Every time i fix something something else breaks. Just finished putting in a new transmission valve body filter and oil in on friday. start it up and drive it around my shop a few times and everything seemed to be working great i was happy. I go to drive it home and i make it about a half a mile from my shop and my tach and nav screen go out and then every light on the dash lights up along with trans fail safe and self level inactive. Now i'm looking for a big tree to run into! Got it back to my shop and shut it off for about 5 minutes. started checking connections and everything looked good. Battery voltage was 12.8. Started it back up with my meter on the battery. voltage dropped to around 11 and then back up to 12.8 after it was started. Hit the gas and the voltage Jumped up to 14.6 then back down to 12.5 and it did this for a few minutes. when i held the engine at around 3000 rpm it jumped up to over 16 to 17 volts and all the lights on the dash came back on. I'm thinking it a bad alternator or at least a bad regulator. I'v been reading on here all weekend and i guess ill start with a new regulator and go from there. I have 40,924 miles on this thing and it is falling apart! My list of repairs is a mile long so far. Any thing else I should look for please let me know.
thanks

alternator quite possibly is toast.

Replace the alternator before your electronics are toast.

Sounds about right.

Fluctuating voltage is typically a sign of a bad alternator.

Had the alternator tested today and its a bad regulator. ordered a new one from BMW for 105.00 it will be here thursday.

At 40,000 miles? Wow. Knock on wood I ahve not seen a dash light in over a year. 102,000 miles and going strong.

Good luck. Keep us posted and not abandon the thread after you have the problem fixed. It might help others when searching for solution of their own problem.

Here's a warning of things that will likely break....

Radiator
Water pump
Alternator
Drivers door handle
Driver's window regulator
Final Stage resistor
Mass Air Flow Sensor
O2 sensor(s)
Water pump
Power Steering hoses
Fuel Vapor Valve
Pixel display in Instrument Cluster
Transmission

Oh yeah, forgot the taillamp sockets. But I posted a DIY on how to fix those...

My wife's girlfriend and her husband just got rid of their 3.0 X5 last weekend, traded it in on a new Nissan Armada, they'd had enough. The damn thing broke down on them two weekends ago on the Bay Bridge while traveling to San Francisco to meet up with some other friends for the day.

Picked up the new voltage regulator from BMW saturday and installed it on the alternator. Alternator is putting out almost 15 volts. Did not know these had 14 volt alternators on them. Drove it around all day today with no problems transmission is working like when it was new. Next is the stereo. After it is turned on the whole right side shuts off after about 20 seconds. Not sure whats going on there or if i should fix it or rip it all out and go aftermarket. Getting it looked at this week I hope.