New Alternator. New Battery. Still having power drains/issues - Page 2 - E46Fanatics E46 BMW Social Directory E46 FAQ 3-Series Discussion Forums BMW Photo Gallery BMW 3-Series Technical Information E46 Fanatics - The Ultimate BMW Resource BMW Vendors General E46 Forum The Tire Rack's Tire Wheel Forum Forced Induction Forum The Off-Topic The E46 BMW Showroom For Sale, For Trade or Wanting to Buy

Welcome to the E46Fanatics forums. E46Fanatics is the premiere website for BMW 3 series owners around the world with interactive forums, a geographical enthusiast directory, photo galleries, and technical information for BMW enthusiasts.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us.

Go Back   E46Fanatics > E46 BMW > General E46 Forum

General E46 Forum
This is the place to get answers, opinions and everything you need related to your E46 (sedan, coupe, convertible and wagon) BMW!

Thread Tools Search this Thread Rating: Thread Rating: 10 votes, 5.00 average. Display Modes
Old 01-20-2016, 03:42 PM   #21
Registered User
dmax's Avatar
Join Date: Aug 2006
Location: NJ
Posts: 23,732
My Ride: '99 328i 300K miles
Not sure how you tested it in the car, but if it benchtested at 14v, I'm thinking the alt is good...the connection might be bad. A bad pulley wouldn't lower the voltage that much without showing other signs, like weak Power Steering.

If the issue is you're draining quickly...could be the battery...grounds...some loose connection.

Also, a bad FSR is the most common cause for the car draining overnight. Put that on the list of things to consider. Note jfoj's post above with detailed methods for diagnosing issues.

Laugh with me! Don't be lame! Broadway Comedy Club, NYC, July 14, 8 p.m. See Facebook for other shows and PM me if you can make one.

Please view this vid so it looks like I'm popular. Please!

dmax on Facebook

Mangofy your E46!
dmax is offline   Reply With Quote
Old 01-21-2016, 09:00 AM   #22
Registered User
Join Date: Jul 2008
Location: USA
Posts: 6,171
My Ride: 2001 330Ci
New Alternator. New Battery. Still having power drains/issues

If you've installed a new battery and a new/rebuilt (by Bosch, hopefully) alternator and your car still is draining you battery, it's time to go hunting.

Get a digital volt/ohm/amp meter. They're cheap at under $15!

- Set the meter to read current (amps/amperes: a measure of electrical energy flow).
- Remove the negative/ground/earth cable from the battery
- Connect one of the meter leads to the battery post
- Connect the other lead to the battery cable


Allow the car to go to sleep. This will take 10-15 minutes. Check the meter. It should say less than 100ma (0.1 amps). Mine reads about 50ma. If it's higher than 100ma the first suspect is the FSR. The FSR can be accessed in the lower dash on the right side of the car. It's job is to provide the heating/ac control unit with many possible fan speeds. They go bad. The usual symptom of a bad FSR is erratic fan speeds. They can also drain the battery when they go bad. Replace it with an OEM FSR.

FSR not the problem?? Start pulling fuses one at a time. That is, pull a fuse, check the meter for a significant drop in current flow, reinsert the fuse when the meter readout doesn't change. Now, just don't pull fuses randomly. Do it by system. For example, if you have an aftermarket head unit and/or amplifier, start with those fuses.

Happy hunting!

Last edited by markusmarkus; 01-21-2016 at 09:02 AM.
markusmarkus is offline   Reply With Quote
Old 01-21-2016, 02:47 PM   #23
Registered User
Join Date: Jan 2016
Location: Augusta
Posts: 3
My Ride: 323i
Thanks for all the input. I feel like an idiot coming here and explaining what happened, but maybe I can help a newb in the future. I didn't have the belt on correctly. I had it going OVER the top pulley instead of under it. This was a simple overlook that was caused by impatience and frustration. Thanks again for the help!
augeagle is offline   Reply With Quote
Old 02-15-2016, 04:33 PM   #24
Registered User
Join Date: Jun 2011
Location: Connecticut
Posts: 18
My Ride: 944
I've been chasing a battery drain problem too and suspect the FSR. But when I tested the fan speeds, everything seemed normal. Can a bad FSR drain your battery but still seem to correctly adjust fan speeds?

EVMadman is offline   Reply With Quote
Old 02-17-2016, 12:31 AM   #25
Registered User
Join Date: Feb 2016
Location: Dallas
Posts: 1
My Ride: Mitsubishi mirage

I'm having the same issues can somebody help me with this problem
Jesus90 is offline   Reply With Quote

alternator, battery, issue

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Censor is ON

All times are GMT -5. The time now is 06:45 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
(c) 1999 - VerticalScope Inc. All rights reserved.