Climate Control Troubleshooting (blower motor, resistor, relay, etc?)

[mboucher70 hotmail.com]

Hi All, I could really use some ideas troubleshooting a fan blower motor problem.  It cut out during a long tortuous drive into
the Ice Storm wilderness of Toronto last night.


 


Bit reluctant to say it’s the fan motor itself, because it
was changed maybe 10,000 miles ago (4 years). 
Also, when the last one went, it was like your typical worn out
electrical motor…would start intermittently...and gave signs it was going.


 


The next thought might be the blower motor resistor.  That went bad and was changed about 18 months
ago.  But when it went the last time, the
failure mode was the fan ran on high non-stop until the ignition was shut off.


 


I checked the 30 amp fuse for the fan, and its good.  


 


The control itself seems good…you can hear it energizing the
various solenoids that open and close the vents as it moves from defrost to
bi-level to auto.


 


One concern is that the radiator fan also doesn’t seem to
come on when the various climate control modes are selected.  If I recall, when it was working correctly, only
“econ” didn’t energize the radiator fan. 
All the other modes (“Auto”, “Window defrost”, “Bi-Level”) put the
radiator fan on low, regardless of the outdoor temperature.


 


Thanks for any thoughts or suggestions.


 


MC

1990 Audi 100 10V, Automatic Climate Control