164 ACC problems

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

One of life's little mysteries is why the auto climate control on the 164 
does not work nearly as well as the essentially identical system in the 
SAAB 9000. But it doesn't.

My 91 164L has an automatic climate control that has never worked well from 
new. All electricals are in as new condition. The steppers and distribution 
drum have been done. The heater core does not and never has leaked. the 
thermostat has been replaced once. the radiator has been replaced once. The 
rad fan works flawlessly. Even the temp gauge/warning light has been fixed.

The darned system just does not work properly.

Problem is the cabin temp sensor is in the roof console. So, when the 
weather is hot the AC is too cold. When the weather is cold the heater is 
too hot. When the temperature reaches the low 70's (low 20's for us 
Canucks; Celsius that is, we may be tough about weather but we ain't stupid 
about it) the heat/cool just dithers all over the place depending on sun 
load, wind, etc.

The SAAB has a sun sensor which seems to make a big difference. The other 
factor seems to be the SAAB guys actually wrote some software that works.

However, if the heater won't quit unless you turn it right down or the AC 
won't quit until you turn it right up then probably the cabin air sensor is 
toasted.

Cheers


Michael Smith
White 1991 164L
Original owner
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