Electrical Nightmare

[jcon1334]

So this has been ongoing over serveral weeks. It started while I was driving down the highway then suddenly the radio interrupts, the vent fan interupts and suddenly my idrive display is full of warnings, my instrument cluster is full of warnings and my speedometer is reading 0mph going down the highway. I shut it down at the next stop and some of the stuff came back. The next morning everything was back online. I took it to the dealership and they pulled the codes and said it was reading low voltage and that was the cause of those problems and that my aftermarket battery was to blame--i havent touched the battery since i got the car and it has worked fine for 3 years. So i leave and it was fine for a while...

This week I am driving down the highway and take an exit ramp (probably a little faster than i should have) and the dynamic drive picks that as the time to go away--not ideal!! That scared me enough that monday I took it to the dealership. Again they said the only code was low voltage and that a new battery would be about $500 installed. I took it back in on wednesday to have that done. I picked it up today and he said it would be good to go now and they took it on 2 test drives...

I get about 6 miles from the dealership and things start going to hell in a handbasket...
Here is the list of things that happened literally over a dozen times on my 15mi drive home (dealership was closed or i would have turned right around):

Control Systems Failed
Dynamic Drive Failed
Speedometer intermittent
ABS failed
Flat tire monitor Failed
Radio and fan intermittent
idrive display intermittent but radio would still play
idrive would completely shut down and reboot
DBS malfuntion (that cleared itself before i could get to the screen to see what it means)
I stopped at a friends house and when i started it i had very little power steering but it came back 6-9 seconds later...

Any ideas as to what is causing this debacle (since the dealership cant figure it out...)????

[jcon1334]

BTW the car is a 2005 545i!

[jim165]

Have you checked the alternator? Car could be running strictly on battery....crank the car, undo the negative batt cable and see if the car stops running or take to AutoZone

[jcon1334]

I don't have any problems with the battery dying--it will run for hours and always starts up just fine... I might try that here in a bit, but I don't expect to find anything unusual...

[jim165]

Electrical problem (http://www.bimmerfest.com/forums/showthread.php?t=316911) check this thread and see if it might help?

[Jaycal3]

Is your passenger floor wet at all? If so your storm drains may be clogged forcing water to back into the vehicle... I will spare you the details in case its not the problem but here is my thread:
http://forums.5series.net/topic/107340-545i-flooded-worst-day-in-my-short-bmw-life/page__p__1277480__fromsearch__1#entry1277480

Could be a battery/alternator issue though...

[jcon1334]

Just tried Jim's idea--car ran fine. As far as water, I live in Las Vegas--I can't tell you the last time water was a factor but I will take a peek at it in a bit

[jim165]

Did you by chance check out the link I posted in Post #5? I just read through all 4 pages it in-depth and it looks like in the end, it's the alternator after all. Some suggested replacing one of the charging regulator modules located in the trunk under the spare tire for $20, and it worked for some. However, a majority of them stated that it's the replacement of the alternator/regulator that ultimately fixed the issue. Regulator can be replaced separately...unit is being quoted at about $120. You can try taking to Autozone for a quick free test. Good luck!

[jcon1334]

Yeah those problems in that link looks familiar. I'm going to go digging in the trunk and see what looks/feels odd... And since I still have an extended warranty I will definitely be showing my service manager these posts in the morning... And other ideas are still appreciated until then!!!

[jcon1334]

Update: so I tore my trunk apart and checked for that 1x1x1 block listed on one of the posts in Jim's link--car has been off for about 4-5 hours and I couldn't touch it for more than 5 seconds!! Based on those posts, I suspect that's the culprit (and not the battery that I just bought!!!) I'll give an update tomorrow! I think I'm going to have a hard time getting a refund for the battery I just bought from the dealership though...

[jcon1334]

Took it to the dealership yesterday (friday) morning. They are as frustrated as I am... By the end of the day they werent able to pin it down--they changed that relay box but it still had the problems. So they are keeping it over the weekend and are going to try again today and monday to figure it out. Unfortunately I was supposed to drive to TX monday morning, looks like that will be tuesday now! The good news is they gave me a 2013 X5 as my loaner until its fixed!

[jim165]

...$2 bet that it's the alternator/regulator!

[alexzxn]

I had a 745LI before did almost the exact same thing turns out it need a new alternator.

[2002DAY]

New alternator bro... Had the exact same problem a couple of months ago dash would light up like a Christmas tree when driving. Some days it would be fine others it would go crazy. It progressively got worse while trying to figure it out. Took it to my mechanic and we replaced the alternator never had the problem again.