Expert: Brad Sears - 9/18/2008

Question
QUESTION: Hi Brad,
I have an original 1967 Impala SS with the Comfortron auto temp. system. The A/C compressor will not shut off unless the selector is in the OFF or De-Ice positions. All vacuum connections appear good under the dash (dash is out for inspection presently). The diverter door seem to move to the correct position when in the heat mode, if I unplug at the compressor it works in the heat mode when dial is set to the heat range....any ideas? Thank you!!!

ANSWER: In many of those automatic systems the compressor stayed on as long as the outside temperature was above freezing. This allowed the system to blend heat and cool as well as dehumidify the air in the cabin. There was a throttle suction valve in the system that controlled the flow of freon through the system to keep the evaporator from freezing over. Remember that fuel economy was not a concern in 1967, luxury and performance was top dog.
Brad

---------- FOLLOW-UP ----------

QUESTION: Thanks, that makes senses now. Another question, the blower fan will come on when the selector is moved to a 'working' position. Sometimes it won't in any position unless it moved all the way to the right, then it works in all the positions on the way back. Any ideas....then I'll leave you alone (until the next time)?

Answer
If the system is calling for heat or warm the fan will not come on until the engine temp is up to about 135 degrees F. It will come on all the time when moved to defrost or defog and then over ride on the way down. So, I will wait until next time.
Brad