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Old 08-05-2011, 01:26 PM   #1
Registered User
Join Date: Oct 2007
Location: rochester ny
Posts: 166
My Ride: 2001 330 xi
Parasitic current draw

hello, i have a 2001 330 xi, auto trans, 88 k, well maintained, driven in upstate NY winters. The battery/car has been discharging is it sits for a few days and the car is dead and won't turn over. I am not getting any OBDII codes, I have replaced the battery twice just to make sure. It is an AutoZzone duralast battery.

I am considering replacing the FSR (Final Stage Resistor), the FSR is associated with the A/C or Heater blower, I have not seen it act weird when in "auto" mode, but i'm watching it. I know that fuses #28 (5amp) and #50 (40 amp) are associated with the blower. Are these the correct ones to disconnect to troubleshoot the problem ?

I have a Fluke recording VOM , I put it inline with the positive battery terminal in the trunk. should I have used the negative ? The readings are as follows:

driver's door opened >2 amps
When driver's door is first closed, not asleep yet 200 ma
after 10 mins (sleep mode) min = 8 ma, max = 60 ma, avg = 16 ma.

I'm wondering how to get the blower to turn on (when the key is off and the car is in sleep mode after 16 mins) to test the FSR ? I ran my current draw test with the fuses plugged and unplugged and saw no difference. My next step is to replace the FSR (64-11-6-920-365) as it seems to fix most issues like this.


The batteries are rated for 80 AH, that's amps times hrs. So if you are at the bmw spec. of 40 ma (milliamps) and 80 AH battery should take 83 days to discharge. To discharge in 5 days or so you would need an average drain of more like 600 ma.

So I'm puzzled, I checked battery terminals for corrosion, I looked at the engine compartment battery terms, they look good, I have no aftermarket stuff installed that could go bad. Would I be able to detect a current drain caused by corrosion using the inline amp meter method, It seems to me that it should. My guess is that corrosion on the + terminal is worse than on the -.

Can anyone help solve my issue. I tried to write this up in such a way that once we solve it, it will help others.

Thanks, DC

Last edited by celluloidheros; 08-07-2011 at 05:37 AM.
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