On Thu, 21 Mar 2013 15:22:42 +0000 (UTC), Bimmer Owner
> wrote:

>On Thu, 21 Mar 2013 03:55:47 -0700, the will wrote:
>
>> Blower motor drawing too much amperage taking it out.
>> Change the blower motor anytime?
>
>This is an interesting approach, given that the vast majority of
>bimmer owners do NOT replace the blower motor - they replace the FSU.
>
>While the blower motor replacement procedure is a major PITA, one
>'can' test the leads from the FSU harness connector pins #5 and #1
>which are power and ground respectively to the blower motor.
>
>Again, we don't have a circuit diagram, but it has been said that
>the blower motor takes about 6 amps (variously, depending on the speed)
>but it would take a test jig to test that in operation.
>
>To my knowledge, nobody has created that test jig (although I know
>of only one attempt, which failed):
>http://www.bimmerfest.com/forums/sho...&highlight=fsu
>
>It's easy enough to test the resistance of the blower motor though,
>and those results have come out at about 0.4 to 0.6 ohms.
>
>It would be expensive to change a blower motor on a whim, so, how
>would YOU suggest the blower motor be tested in situ?


If one replaces one of these perhaps it would be advisable to put a
fuse in the blower motor lines (it sounds like those can be gotten to
easily unlike the motor itself). If it's being blown by intermittent
high current draws the fuse could protect the $100 FSU. Another
option would be, at least for those who can live without the highest
blower setting and who think excess current draw is the culprit, would
be to put a power resistor in the blower motor line to limit the
current a bit. On the cheap pedestrian cars I drive the whole speed
control is just a trio of power resistors placed in the air flow to
help cool them. If they burn out (which is rare) they can sometimes
be fixed with a pop rivet.