164 steppers and mirror switch

[C M Smith <cmsmith@domain.elided>]

No, the door panel need not come off to replace the mirror control switch. 
Yes, it's the switch. The Bosch switches on the 164 are prone to failure. I 
watched the mechanic put mine on in five minutes, no charge for labour!

The steppers are a big deal. Lots of info accessible from the Alfa 164 home 
page. Brad Anesi writes very clear and comprehensive how to articles which 
can be accessed from the 164 home page, I recommend them whether you intend 
to do the work yourself or have a mechanic do it. it gives you a healthy 
perspective on the challenges this job entails.

The steppers operate even if the ACC is switched "off". It never sleeps so 
long as the ignition is on. When the ACC is switched off, the temperature 
mixing flap motor rotates the flap to full closed (i e cold position) and 
the recirculation motor (not one of the infamous steppers but a stepper 
type motor of a different design, located on the end of the AC evaporator 
housing in the false bulkhead area of the engine compartment) causes the 
recirc flap to close the outside air inlet. The temperature mixing flap 
motor pulses to maintain pressure on the flap to exclude any warm air flow, 
and  depending on how many gear teeth have stripped on your particular 
stepper, the frequency of the ticking can vary. The temp control motor is 
closer to the surface of the dash (just behind the left side of the 
glovebox) and the ticking from that sounds closer than from the stepper 
controlling the air distribution drum deeper in the dash. Also, when the 
ignition is switched off, the recirc flap and temp control flap return to 
these "off" positions, regardless of any manual or automatic settings selected.

When repairing these items ,consider repairing the gearsets only as the 
motors are usually fine. Sources exist in Australia for these bronze gears. 
Also, forget any idea of spending all that time just to replace one motor 
and gearset, do them both, they both break eventually. There is also a fix 
for a known fault with the air distribution drum which cracks, causing the 
motor to lose it's "key" and cause random distribution settings (grrrh). 
the fix is a metal reinforcing ring installed on the end of the drum 
(whether it's cracked yet or not), before installing the stepper motors on 
their robust one piece bracket.


Michael Smith
Calgary, Alberta
Canada
91 Alfa 164L, White, original owner

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