Heavy Amperage Draw & Dead Battery

lagerstedt · #1 11-23-2009, 02:47 PM

Hello Everyone:

This is my first post for my beloved 4.6is. I have to admit that I have used this site to diagnose/repair my fair share of issues with the X.

Quick history about me: ex-diesel mechanic turned sales guy. I work on my friends cars in exchange for scotch. Only the peaty stuff, though. Lagavulin, Laphroaig, and Arbeg. Enough about me...

I absolutely love working on the X. It has been in my opinion a fantastic SUV. I drive the hell out of it and it has just been phenomenal. It has 105,000 on it and has recently received a new water pump, alternator, front drive axles ($56 from Napa each rebuilt!) and lots of brake pads. My current gremlin is a heavy amperage draw that drains the battery every night. Sometimes the amp draw is 4.0+/- and sometimes it jumps up to 16.5 +/-. I just bought a new battery, as I still had the OEM one in it. I assumed that it was just getting old. Replaced it and still had the same problem. I hired my 7 year old to stand and hold the fluke meter while I performed the "pull-the-fuse-watch-the-amperage-draw" routine. Pulled every fuse and no drop exept for the dome lights.

I believe that the high amperage draw is coming from my starter solenoid sticking. I say this because sometimes when I go to start it, it just does on "click" and then nothing. The next turn of the key it always fires right up. Again, this is intermitent. Couple time a month. Since the new battery change, the heavy amp draw is intermitent, too. I plan on taking out the starter and seeing if there is anyway to remove the solenoid, clean/lube it and see if that fixes the problem. A new starter is about $200, so I figure I would see if I can just fix it old-school.

Any help would be appreciated and I will try and post pics of my next project.

Regards,

lagerstedt

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CarveRoad · #2 11-24-2009, 12:52 PM

I never measured the amp draw when I had this problem, but pulling fuse #74 as described in post #12 cured it. Still running the same battery 1-1/2 years later. I don't use any of the associated telephone modules.

http://www.xoutpost.com/bmw-sav-foru...ain-issue.html

Chris Peterson
Las Vegas

John Galt · #3 11-24-2009, 01:12 PM

Quote:

Originally Posted by lagerstedt

My current gremlin is a heavy amperage draw that drains the battery every night.

Considering the variable level of draw, I suspect the final stage resistor.

http://www.xoutpost.com/bmw-sav-foru...r-car-off.html

http://www.xoutpost.com/articles/x5/...placement.html

After you turn the car off, put your head under the dash and listen for a fan running. The final stage resistor may be keeping the fan running at a low level when the engine is off, thereby draining your battery. Even if you cannot hear a fan running, I would pull your final stage resistor and look at it to see if it has any burn marks on it. Replace it if it does.

lagerstedt · #4 11-24-2009, 02:29 PM

Thanks! I just pulled the #74 (telephone) fuse and will check the resistor this evening. I know for a fact that the fan fluctuates in speed after the vehicle has been turned off.

John Galt · #5 11-24-2009, 07:34 PM

Quote:

Originally Posted by lagerstedt

Thanks! I just pulled the #74 (telephone) fuse and will check the resistor this evening. I know for a fact that the fan fluctuates in speed after the vehicle has been turned off.

If the fan is on at all after the car is turned off, it is almost certainly the final stage resistor. I would replace it ASAP.

Weasel · #6 11-24-2009, 08:30 PM

The fluctuating heavy draw and fan on after ignition off both confirm it.... you need a FSR. Very easy repair, will only take you a few minutes.

Hopefully you remember that it takes at least 16 minutes for the X5 to go fully to sleep too.

killcrap · #7 11-24-2009, 09:23 PM

Quote:

Originally Posted by Weasel

The fluctuating heavy draw and fan on after ignition off both confirm it.... you need a FSR. Very easy repair, will only take you a few minutes.

Hopefully you remember that it takes at least 16 minutes for the X5 to go fully to sleep too.

and a fully charged battery.

lagerstedt · #8 11-30-2009, 02:49 PM

Guys:

Got it! Purchased the FSR two nights ago from Strictly BMW in Bellevue and replaced it in the X. Cured the battery draw problem. I also took out fuse #74 just in case...

Thanks for the help and suggestions - it saved me from having to take out my starter.

Paul

faz · #9 11-30-2009, 04:14 PM

Great.

Now hopefully you will start to frequent this site more often and share/contribute some of your knowledge/experience to help others here too.

celicatoe46m3 · #10 12-18-2009, 06:03 AM

OK I'm reading this problem and this is exactly the problem I am having with my 4.6iS. Replaced battery, alternator and still dying over 2 nights after fully charged. I'm electrically challenged, but what should I do? Pull that fuse #74?

My fan I notice actually turns off, and then it sounds like its on, and then its off, and does this on/off thing for about 1-2 minutes, and it sounds off after that. Should I check the FSR as well?

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