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Old 02-07-2013, 05:55 PM
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bluebee bluebee is offline
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Location: San Jose, California
Join Date: Mar 2008
Posts: 25,236
Mein Auto: 02 BMW 525i M54 auto 130K
Originally Posted by Fudman View Post
For your troubleshooting sequence, I would recommend pulling the FSU first rather than pulling fuse 76 for the following reasons
I agree with you and will update the procedure so others don't make the same mistake I just did.
In fact, I just pulled the FSU, after decrying that the Germans are still getting back at us for what we did to Dresden in the daylight, way back in 1945, by designing that diabolical God awful FSU harness connector (which broke, again, in my clumsy hands).
You need three (tiny) hands:
1. One hand to hold the flashlight
2. Another to press the clips on the harness connector
3. And a third hand to pull the fsu away from the harness connector

Originally Posted by Fudman View Post
I would still pull your FSU and check it out. It is the only really accesible component on the heater blower circuit that has a history of causing this exact failure.
For others following this, I concur with Fudman that pulling the FSU is a wiser move than pulling the fuse F76 because of the following:
a) Pulling fuse F76 is a general test while pulling the FSU is a specific test
b) Pulling & replacing the FSU is actually slightly EASIER (if you can believe that) than pulling & replacing the yellow 40A fuse F76.
c) If the problem turns out to be the FSU, you have to pull it anyway to replace it.

Originally Posted by vatoman View Post
How many mile do you have?
I have 112K miles on my 2002 which I had bought still under the factory warranty so I'm only the second owner.

In order to isolate the problem, I'm now going to run some amperage tests with the FSU removed and the fuse F76 back in place.
Here is the replacement FSU I just pulled, next to the original FSU I saved all these years (waiting for a round tuit to finally autopsy it).

Originally Posted by Fudman View Post
did you buy your FSU from the dealer?
Unfortunately, I did NOT buy my replacement FSU from the dealer.
This receipt, from late January of 2009, that I posted to the forums shows I bought it from AutoHauzAZ (before I knew about Max).
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Please read the suggested threads and add value, either by pictures or by descriptions, so the next person stands on your shoulders.
See also: E39 Bestlinks & How to easily find what you need

Last edited by bluebee; 02-07-2013 at 06:02 PM.
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