On Thu, 21 Mar 2013 11:45:54 -0400, Scott Dorsey wrote:

Static resistance doesn't tell you anything, but operating current
measured with a DMM would tell you a lot.

It 'can' be done, but would require a test jig inserted inline
as the FSU is deeply ensconced under the dash while the blower motor
is even more deeply so.

I've never tested one, but I put a drop of turbine oil on the
motor bearings every five years or so.

While that preventive work might be prudent, the sheer effort
to remove the entire dash simply to access the blower motor
would be problematic.

Still, if the problem is that the blower motor is merely using more
current as it gets older, why wouldn't a NEW FSU burn up within a
few weeks of insertion?