Multiple Issues? ABS/DSC/Brake light and Dead Battery/Battery light

jizay · #1 10-20-2007, 12:29 PM

Hello everyone, I've been trying to find a post with a similar issue to mine, but am only finding pieces.

The other day the ABS/DSC/Brake lights came on along with the Battery light, then the Trans Failsafe Prog popped up. The X5 felt like it was in top gear off the line, no pull what so ever. The A/C panel also went extremely dim and the blower stopped blowing, then all of the sudden the A/C blower cranked all the way up. I parked the X5 (2002) and the next day battery was dead. Replaced the battery and cranked up. The ABS/DSC/Brake lights come on intermitently now and the Battery light never goes away. I havent seen the Trans Failsafe Prog again though. The speedo still works as does the cruise control. So, parked the car, and overnight the new battery was dead. Started cruising through the posts and found some people having their Business CD player repleced (turns on after the car is off and draws current apparently) so I disconnected the CD Player and the next day it was dead again. I've also read about the Final Stage Resistor having issues. I just unplugged that and we'll see if that drains the battery tonight.

When I drive the car though, if I let off the throttle the ABS/DSC/Brake light go out, once I get back on the throttle it's christmas again. The battery light never goes out, but using the Checkout Control the voltage on the battery is about 13.5V idling, and as high as 16+ V under throttle. It appears that the alternater is working.

I cant figure out why the battery light will not go out.

Anyone have any suggestions for any of this? Is the battery light issue tied to the other lights or are these separate issues? I appreciate the help.

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NOVAX5 · #2 10-20-2007, 12:45 PM

Yep, i posted this before. alternator it is. search for my post.

jizay · #3 10-20-2007, 01:17 PM

Its the alternator, even though its putting out 16.4 Volts when driving and 13.5 at idle?

Did you take the car to Autozone or something to have them check the alternator?

I'll try to find your post in the meantime. Thanks for the info.

jizay · #4 10-21-2007, 11:39 AM

I disconnected the Final Stage Resistor and the car is dead again. I'm going to jump it and drive up to have the alternator checked out, but it seems odd that it would be the alternator when its putting out normal voltage readings, and the battery dies when the vehicle is off overnight.

Anyone else have any suggestions?

Zulu95 · #5 10-21-2007, 01:34 PM

16.4 V driving and 13.5 at idle are not normal readings for a Bosch alternator. The regulator in these things should hold the charging voltage somewhere around 13.8V. Could be a faulty regulator in the alternator.

flip_x · #6 10-21-2007, 06:19 PM

I have the same problem... i thought the alt was bad too.. but been driving it for 2.2k miles on that since it happend... all that happens right now is the batt shows signs of dying for me... the other day it woulnt start because it was too cold but when i got it jumped the battery starts up in the cold again.. weird but the batt light is still on..

jizay · #7 10-21-2007, 07:52 PM

Had the alternator checked out at Discount Auto, everything looked good. 16+ Volts seemed high to me too, but I've read other posts stating a 13.5V idle readin. Still not sure what to do. A/C still comes on an off intermittently. Actually it seems like while accelerating the A/C shuts off (in conjunction with the higher voltage), then as I slow down it comes back on again. This is really pissing me off, I've already spent $140 on a battery I probably didnt need. While looking at my drive belt from underneath, I've noticed a slight leak at the cheap @ss crimp connection used to mate two of the rubber powersteering hoses, as well as bubbling on one of the hoses. This is not the experience I had expected from BMW. It makes no sense that after 2 years of no issues, one day the entire dash lights up and there's a ghost in the machine.

jizay · #8 11-02-2007, 01:15 AM

I pulled the alternator and had it tested. It wouldnt even run the full test at the store, it would just shut their machine down. I noticed that everytime the voltage got above 16.1 Volts the A/C would shut down.

So I bought a new one and installed it. It was the voltage regulator on the alternator. The new one maintains 13.5 ~14.5 volts and no more issues (yet). I havent driven too far yet though. When I started working on the alternator I found the rubber power steering hose had a leak and looked to be in bad shape. I did drive the car about a mile after the new alternator install and no dash lights and good voltage. I just finished the power steering hose tonight, so I'll drive it to work tomorrow and see what happens.

Almost forgot, no more dead battery either. I guess the voltage regulator had a short that was draining the battery even while the car was off.

Hopefully no more issues. Thanks for everyone's input. By the way, if you need an alternator buy it from Advanced Auto Parts (the old Discount Auto) for $250 (w/lifetime warranty) instead of the $800+ part the dealer offers.

fatboyoz · #9 11-02-2007, 01:30 AM

Quote:

Originally Posted by Zulu95

16.4 V driving and 13.5 at idle are not normal readings for a Bosch alternator. The regulator in these things should hold the charging voltage somewhere around 13.8V. Could be a faulty regulator in the alternator.

Spot-on Zulu.

Colin.

jizay · #10 11-03-2007, 03:03 AM

Yep, it was the voltage regulator. New alternator did the trick.

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