"Bimmer Owner" wrote in message
...
On Thu, 21 Mar 2013 15:03:45 -0700, Ashton Crusher wrote:

If it's being blown by intermittent high current draws the
fuse could protect the $100 FSU.

That's an interesting idea. The FSU supposedly consumes the
most power when the blower motor is set to the LOW settings
(simply because it has to dissipate the power as heat), so,
we could prevent excess current by fusing... say with a 10A
fuse, the blower motor (which is said to consume 5 to 6 A).


Are you sure it is not already a pulse width regulator? Those transistors
look like they are TO-220 packages, not TO-3.
PWM has been around longer than SMT parts.

Maybe it is transients from the motor that are causing the failures.

Another place you could measure the current is by putting an ammeter in
place of the blower motor fuse.


tm